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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html;charset=UTF-8"/>
<link rel="icon" type="image/gif" href="/favicon.gif"/>
<link rel="apple-touch-icon" sizes="120x120" href="touch-icon-iphone-retina.png" />
<link rel="apple-touch-icon" sizes="152x152" href="touch-icon-ipad-retina.png" />
<title>Lorem Ipsum</title>
<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
<style type="text/css" id="internal-style">
@import url(hyperpolyglot.css);
</style>
<meta http-equiv="content-type" content="text/html;charset=UTF-8"/>
<meta http-equiv="content-language" content="en"/>
</head>
<body>
<div id="container-wrap-wrap">
<div id="container-wrap">
<div id="container">
<div id="header">
<h1><a href="/"><span>Hyperpolyglot</span></a></h1>
</div>
<div id="content-wrap">
<div id="main-content">
<div id="page-title">Lorem Ipsum</div>
<div id="page-content">
<p><a name="top"></a><em>a side-by-side reference sheet</em></p>
<p><a href="#grammar-invocation">grammar and invocation</a> | <a href="#var-expr">variables and expression</a> | <a href="#arithmetic-logic">arithmetic and logic</a> | <a href="#strings">strings</a> | <a href="#regexes">regexes</a> | <a href="#dates-time">dates and time</a> | <a href="#arrays">arrays</a> | <a href="#dictionaries">dictionaries</a> | <a href="#tables">tables</a> | <a href="#relational-algebra">relational algebra</a> | <a href="#aggregation">aggregation</a> | <a href="#functions">functions</a> | <a href="#execution-control">execution control</a> | <a href="#files">files</a> | <a href="#libraries-namespaces">libraries and namespaces</a> | <a href="#reflection">reflection</a></p>
<table class="wiki-content-table">
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="version-used"></a><a href="#version-used-note">version used</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td><span style="color: gray"><em>PostgreSQL 9.0</em></span></td>
<td><span style="color: gray"><em>20070501</em></span></td>
<td><span style="color: gray"><em>0.9</em></span></td>
</tr>
<tr>
<td><a name="show-version"></a><a href="#show-version-note">show version</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td><span style="white-space: pre-wrap;">></span> SELECT version();</td>
<td>$ awk <span style="white-space: pre-wrap;">--</span>version</td>
<td>$ pig <span style="white-space: pre-wrap;">--</span>version</td>
</tr>
<tr>
<th colspan="4"><a name="grammar-invocation"></a><a href="#grammar-invocation-note">grammar and invocation</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="interpreter"></a><a href="#interpreter-note">interpreter</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>$ psql -f foo.sql</td>
<td>$ awk -f foo.awk bar.txt</td>
<td>$ pig -f foo.pig</td>
</tr>
<tr>
<td><a name="repl"></a><a href="#repl-note">repl</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>$ psql</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>$ pig -x local</td>
</tr>
<tr>
<td><a name="input-format"></a><a href="#input-format-note">input data format</a></td>
<td><span style="color: gray"><em>multiple tables defined by</em> create table <em>statements</em></span></td>
<td><span style="color: gray"><em>single field and record delimited file. By default fields are delimited by whitespace and records by newlines</em></span></td>
<td><span style="color: gray"><em>multiple files. Default loading function is</em> PigStorage <em>and default delimiter is tab</em></span></td>
</tr>
<tr>
<td><a name="statement-separator"></a><a href="#statement-separator-note">statement separator</a></td>
<td>;</td>
<td>; <span style="color: gray"><em>or newline</em></span></td>
<td>; <span style="color: gray"><em>and newline when using REPL</em></span></td>
</tr>
<tr>
<td><a name="block-delimiters"></a><a href="#block-delimiters-note">block delimiters</a></td>
<td><span style="color: gray"><em>none in SQL; PL/SQL uses keywords to delimit blocks</em></span></td>
<td>{ }</td>
<td> </td>
</tr>
<tr>
<td><a name="eol-comment"></a><a href="#eol-comment-note">end-of-line comment</a></td>
<td><span style="white-space: pre-wrap;">--</span> <span style="color: gray"><em>comment</em></span></td>
<td># <span style="color: gray"><em>comment</em></span></td>
<td><span style="white-space: pre-wrap;">--</span> <span style="color: gray"><em>comment</em></span></td>
</tr>
<tr>
<td><a name="multiple-line-comment"></a><a href="#multiple-line-comment-note">multiple line comment</a></td>
<td><span style="color: gray"><em>none</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
<td><span style="color: gray">/* comment<br />
another comment */</span></td>
</tr>
<tr>
<th colspan="4"><a name="var-expr"></a><a href="#var-expr-note">variables and expressions</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="case-sensitive"></a><a href="#case-sensitive-note">case sensitive?</a></td>
<td><span style="color: gray"><em>no</em></span></td>
<td><span style="color: gray"><em>yes</em></span></td>
<td><span style="color: gray"><em>functions and aliases are case sensitive; commands and operators are not</em></span></td>
</tr>
<tr>
<td><a name="quoted-id"></a><a href="#quoted-id-note">quoted identifier</a></td>
<td>CREATE TABLE "select" (<br />
<span style="white-space: pre-wrap;"> </span>"foo bar" INT<br />
);<br />
<br />
<span style="color: gray"><em>MySQL:</em></span><br />
CREATE TABLE <span style="white-space: pre-wrap;">`select`</span> (<br />
<span style="white-space: pre-wrap;"> </span> <span style="white-space: pre-wrap;">`foo bar`</span> INT<br />
);</td>
<td><span style="color: gray"><em>none</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="null"></a><a href="#null-note">null</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>NULL</td>
<td>""</td>
<td>null</td>
</tr>
<tr>
<td><a name="null-test"></a><a href="#null-test-note">null test</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>foo IS NULL</td>
<td>foo == ""</td>
<td><span style="color: gray"><em>in filter clause:</em></span><br />
is null</td>
</tr>
<tr>
<td><a name="coalesce"></a><a href="#coalesce-note">coalesce</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>coalesce(foo, 0)</td>
<td> </td>
<td>foo is null ? 0 : foo</td>
</tr>
<tr>
<td><a name="nullif"></a><a href="#nullif-note">nullif</a></td>
<td>nullif(foo, -999)</td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="conditional-expr"></a><a href="#conditional-expr-note">conditional expression</a></td>
<td>CASE WHEN x > 0 THEN x ELSE -x END</td>
<td>x > 0 ? x : -x</td>
<td>x > 0 ? x : -x</td>
</tr>
<tr>
<th colspan="4"><a name="arithmetic-logic"></a><a href="#arithmetic-logic-note">arithmetic and logic</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="boolean-type"></a><a href="#boolean-type-note">boolean type</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>BOOLEAN</td>
<td><span style="color: gray"><em>values are untyped</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="true-false"></a><a href="#true-false-note">true and false</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>TRUE FALSE</td>
<td>1 0</td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="falsehoods"></a><a href="#falsehoods-note">falsehoods</a></td>
<td>FALSE<br />
<br />
<span style="color: gray"><em>the predicate of a</em> where <em>clause evaluates as false if it contains a null</em></span></td>
<td>0 ""</td>
<td><span style="color: gray"><em>none; the first operand of a conditional expression must be a comparison operator expression</em></span></td>
</tr>
<tr>
<td><a name="logical-op"></a><a href="#logical-op-note">logical operators</a></td>
<td>AND OR NOT</td>
<td>&& @</td>
<td>@@ !</td>
<td><span style="color: gray"><em>in filter clause:</em></span><br />
and or not</td>
</tr>
<tr>
<td><a name="logical-expr"></a><a href="#logical-expr-note">logical expression</a></td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="relational-op"></a><a href="#relational-op-note">relational operators</a></td>
<td><span style="white-space: pre-wrap;">=</span> != > < >= <=</td>
<td>== != > < >= <=</td>
<td>== != > < >= <=</td>
</tr>
<tr>
<td><a name="int-type"></a><a href="#int-type-note">integer type</a></td>
<td>smallint <span style="color: gray"><em>2 bytes</em></span><br />
int <span style="color: gray"><em>4 bytes</em></span><br />
bigint <span style="color: gray"><em>8 bytes</em></span></td>
<td><span style="color: gray"><em>variables are untyped</em></span></td>
<td>int <span style="color: gray"><em>4 bytes</em></span><br />
long <span style="color: gray"><em>8 bytes</em></span></td>
</tr>
<tr>
<td><a name="float-type"></a><a href="#float-type-note">float type</a></td>
<td>float <span style="color: gray"><em>4 bytes</em></span><br />
double <span style="color: gray"><em>8 bytes</em></span></td>
<td><span style="color: gray"><em>variables are untyped</em></span></td>
<td>float <span style="color: gray"><em>4 bytes</em></span><br />
double <span style="color: gray"><em>8 bytes</em></span></td>
</tr>
<tr>
<td><a name="fixed-type"></a><a href="#fixed-type-note">fixed type</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>numeric(<span style="color: gray"><em>precision</em></span>, <span style="color: gray"><em>scale</em></span>)</td>
<td><span style="color: gray"><em>variables are untyped</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="arith-op"></a><a href="#arith-op-note">arithmetic operators</a><br />
<span style="color: gray"><em>addition, subtraction, multiplication, division, remainder</em></span></td>
<td>+ - * / %</td>
<td>+ - * / %</td>
<td>+ - * / %</td>
</tr>
<tr>
<td><a name="int-div"></a><a href="#int-div-note">integer division</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>13 / 5</td>
<td>int(13 / 5)</td>
<td>13 / 5</td>
</tr>
<tr>
<td><a name="int-div-zero"></a><a href="#int-div-zero-note">integer division by zero</a></td>
<td><span style="color: gray"><em>error</em></span></td>
<td><span style="color: gray"><em>error</em></span></td>
<td>null</td>
</tr>
<tr>
<td><a name="float-div"></a><a href="#float-div-note">float division</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>cast(13 as float) / 5</td>
<td>13 / 5</td>
<td>1.0 * 13 / 5</td>
</tr>
<tr>
<td><a name="float-div-zero"></a><a href="#float-div-zero-note">float division by zero</a></td>
<td><span style="color: gray"><em>error</em></span></td>
<td><span style="color: gray"><em>error</em></span></td>
<td>null</td>
</tr>
<tr>
<td><a name="power"></a><a href="#power-note">power</a></td>
<td>2 ^ 32</td>
<td>2 ^ 32<br />
2 ** 32</td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="sqrt"></a><a href="#sqrt-note">sqrt</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>sqrt(2)</td>
<td>sqrt(2)</td>
<td>SQRT(2)</td>
</tr>
<tr>
<td><a name="sqrt-negative-one"></a><a href="#sqrt-negative-one-note">sqrt -1</a></td>
<td><span style="color: gray"><em>error</em></span></td>
<td><span style="color: gray"><em>generates a warning:</em></span><br />
nan</td>
<td>NaN</td>
</tr>
<tr>
<td><a name="transcendental-func"></a><a href="#transcendental-func-note">transcendental functions</a></td>
<td>exp ln sin cos tan asin acos atan atan2</td>
<td>exp log sin cos <span style="color: gray"><em>none</em></span> <span style="color: gray"><em>none</em></span> <span style="color: gray"><em>none</em></span> <span style="color: gray"><em>none</em></span> atan2</td>
<td>EXP LOG SIN COS TAN ASIN ACOS ATAN <span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="float-trunc"></a><a href="#float-trunc-note">float truncation</a></td>
<td>cast(2.7 as int)<br />
round(2.7)<br />
ceil(2.7)<br />
floor(2.7)</td>
<td>int(2.7)</td>
<td>(int)2.7<br />
ROUND(2.7)<br />
CEIL(2.7)<br />
FLOOR(2.7)</td>
</tr>
<tr>
<td><a name="absolute-val"></a><a href="#absolute-val-note">absolute value</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>abs(-2.7)</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>ABS(-2.7)</td>
</tr>
<tr>
<td><a name="random-num"></a><a href="#random-num-note">random number</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>random()</td>
<td>rand()</td>
<td>RANDOM()</td>
</tr>
<tr>
<td><a name="bit-op"></a><a href="#bit-op-note">bit operators</a></td>
<td><span style="white-space: pre-wrap;"><< >></span> & | # ~</td>
<td><span style="color: gray"><em>gawk:</em></span><br />
lshift(<span style="color: gray"><em>val</em></span>, <span style="color: gray"><em>cnt</em></span>)<br />
rshift(<span style="color: gray"><em>val</em></span>, <span style="color: gray"><em>cnt</em></span>)<br />
and(<span style="color: gray"><em>val1</em></span>, <span style="color: gray"><em>val2</em></span>)<br />
or(<span style="color: gray"><em>val1</em></span>, <span style="color: gray"><em>val2</em></span>)<br />
xor(<span style="color: gray"><em>val1</em></span>, <span style="color: gray"><em>val2</em></span>)<br />
compl(<span style="color: gray"><em>val</em></span>)</td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<th colspan="4"><a name="strings"></a><a href="#strings-note">strings</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="str-types"></a><a href="#str-types-note">types</a></td>
<td>text<br />
varchar(<span style="color: gray"><em>n</em></span>)<br />
char(<span style="color: gray"><em>n</em></span>)</td>
<td><span style="color: gray"><em>variables are untyped</em></span></td>
<td>chararray<br />
bytearray</td>
</tr>
<tr>
<td><a name="str-literal"></a><a href="#str-literal-note">literal</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>'don''t say "no"'<br />
<br />
<span style="color: gray"><em>PostgreSQL escape literal:</em></span><br />
E'don\'t say "no"'</td>
<td>"don't say \"no\""</td>
<td>'don\'t say "no"'</td>
</tr>
<tr>
<td><a name="str-len"></a><a href="#str-len-note">length</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>length('lorem ipsum')</td>
<td>length("lorem ipsum")</td>
<td>SIZE('lorem ipsum')</td>
</tr>
<tr>
<td><a name="str-esc"></a><a href="#str-esc-note">escapes</a></td>
<td><span style="color: gray"><em>no backslash escapes in SQL standard string literals</em></span><br />
<br />
<span style="color: gray"><em>in PostgreSQL escape literals:</em></span><br />
\b \f \n \r \t \<span style="color: gray"><em>ooo</em></span> \x<span style="color: gray"><em>hh</em></span> \u<span style="color: gray"><em>hhhh</em></span> \u<span style="color: gray"><em>hhhhhhhh</em></span></td>
<td>\\ \" \a \b \f \n \r \t \v \<span style="color: gray"><em>ooo</em></span> \x<span style="color: gray"><em>hh</em></span></td>
<td>\n \t \u<span style="color: gray"><em>hhhh</em></span></td>
</tr>
<tr>
<td><a name="str-concat"></a><a href="#str-concat-note">concatenation</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>'Hello' @</td>
<td><span style="white-space: pre-wrap;"> ', ' </span></td>
<td>@@ 'World!'</td>
<td>("Hello" " " "World!")</td>
<td>CONCAT(CONCAT('Hello', ', '), 'World!')</td>
</tr>
<tr>
<td><a name="split"></a><a href="#split-note">split</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>regexp_split_to_array(<br />
<span style="white-space: pre-wrap;"> </span>'do re mi', ' '<br />
)</td>
<td>split("do re mi", a, " ")</td>
<td>STRSPLIT('do re mi', ' ')</td>
</tr>
<tr>
<td><a name="case-manipulation"></a><a href="#case-manipulation-note">case manipulation</a></td>
<td>upper('lorem')<br />
lower('LOREM')<br />
initcap('lorem')</td>
<td>toupper("lorem")<br />
tolower("LOREM")<br />
<span style="color: gray"><em>none</em></span></td>
<td>UPPER('lorem')<br />
LOWER('LOREM')<br />
UCFIRST('lorem')</td>
</tr>
<tr>
<td><a name="strip"></a><a href="#strip-note">strip</a></td>
<td>trim(' lorem ')<br />
ltrim(' lorem')<br />
rtrim('lorem ')</td>
<td> </td>
<td>TRIM(' lorem ')</td>
</tr>
<tr>
<td><a name="index-substr"></a><a href="#index-substr-note">index of substring</a></td>
<td><span style="color: gray"><em>index starts from 1; returns 0 if not found:</em></span><br />
strpos('lorem ipsum', 'ipsum')</td>
<td><span style="color: gray"><em>index starts from 1; returns 0 if not found:</em></span><br />
index("lorem ipsum", "ipsum")</td>
<td><span style="color: gray"><em>index starts from 0; returns -1 if not found:</em></span><br />
INDEXOF('lorem ipsum', 'ipsum', 0)</td>
</tr>
<tr>
<td><a name="substr"></a><a href="#substr-note">extract substring</a></td>
<td>substr('lorem ipsum', 7, 5)</td>
<td>substr("lorem ipsum", 7, 5)</td>
<td>SUBSTRING('lorem ipsum', 6, 11)</td>
</tr>
<tr>
<td><a name="sprintf"></a><a href="#sprintf-note">sprintf</a></td>
<td>select format('%s %s %s', 'foo', 7, 13.2);</td>
<td>sprintf("%s %d %f", "foo", 7, 13.2)</td>
<td>REGISTER /PATH/TO/piggybank-0.3-amzn.jar;<br />
DEFINE FORMAT org.apache.pig.piggybank.<br />
evaluation.string.FORMAT();<br />
<br />
foo = FOREACH foo GENERATE<br />
<span style="white-space: pre-wrap;"> </span>FORMAT('%s %d %f', 'foo', 7, 13.2);</td>
</tr>
<tr>
<th colspan="4"><a name="regexes"></a><a href="#regexes-note">regular expressions</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="match"></a><a href="#match-note">match</a></td>
<td>select *<br />
from pwt<br />
where name similar to 'r[a-z]+';</td>
<td><span style="color: gray"><em>matching inside pattern:</em></span><br />
$1 ~ /^r[a-z]+/ { print $0 }<br />
<br />
<span style="color: gray"><em>matching inside action:</em></span><br />
{ if (match($1, /^r[a-z]+$/)) print $0 }</td>
<td>root_pwf = filter pwf<br />
<span style="white-space: pre-wrap;"> </span>by SIZE(REGEX_EXTRACT(name, '^(root)$',1)) > 0;</td>
</tr>
<tr>
<td><a name="substitute"></a><a href="#substitute-note">substitute</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>select regexp_replace('foo bar', 'bar$', 'baz');</td>
<td>s = "foo bar"<br />
sub(/bar$/, "baz", s)</td>
<td> </td>
</tr>
<tr>
<td><a name="extract-subgroup"></a><a href="#extract-subgroup-note">extract subgroup</a></td>
<td>select (regexp_matches('foobar', '(f..)bar'))[1];</td>
<td> </td>
<td>properties = FOREACH urls GENERATE FLATTEN(EXTRACT($0, '^https?:<span style="white-space: pre-wrap;">//</span>([^/]+)')) as host:chararray;</td>
</tr>
<tr>
<th colspan="4"><a name="dates-time"></a><a href="#dates-time-note">dates and time</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="current-date-time"></a><a href="#current-date-time-note">current date and time</a></td>
<td>now()</td>
<td><span style="color: gray"><em>gawk:</em></span><br />
systime()</td>
<td>REGISTER /PATH/TO/piggybank-0.3-amzn.jar;<br />
DEFINE DATE_TIME org.apache.pig.piggybank.<br />
evaluation.datetime.DATE_TIME();<br />
<br />
bar = FOREACH foo GENERATE DATE_TIME('-00:00');</td>
</tr>
<tr>
<td><a name="date-time-to-str"></a><a href="#date-time-to-str-note">datetime to string</a></td>
<td>to_char(now(), 'YYYY-MM-DD HH24:MI:SS')</td>
<td><span style="color: gray"><em>gawk:</em></span><br />
strftime("%Y-%m-%d %H:%M:%S", systime())</td>
<td>REGISTER /PATH/TO/piggybank-0.3-amzn.jar;<br />
DEFINE FORMAT_DT org.apache.pig.piggybank.<br />
evaluation.datetime.FORMAT_DT();<br />
<br />
baz = FOREACH bar GENERATE FORMAT_DT('yyyy-MM-dd HH::mm:ss', $0);</td>
</tr>
<tr>
<td><a name="str-to-date-time"></a><a href="#str-to-date-time-note">string to datetime</a></td>
<td>to_timestamp('2011-09-26 00:00:47', 'YYYY-MM-DD HH24:MI:SS')</td>
<td><span style="color: gray"><em>gawk:</em></span><br />
mktime("2011 09 26 00 00 47")</td>
<td> </td>
</tr>
<tr>
<th colspan="4"><a name="arrays"></a><a href="#arrays-note">arrays</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="array-literal"></a><a href="#array-literal-note">literal</a></td>
<td><span style="color: gray"><em>PostgreSQL:</em></span><br />
create temp table foo ( a int[] );<br />
insert into foo values ( '{1,2,3}' );</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>one_row = LOAD '/tmp/one_line.txt';<br />
foo = FOREACH one_row GENERATE (1,2,3);</td>
</tr>
<tr>
<td><a name="array-size"></a><a href="#array-size-note">size</a></td>
<td><span style="color: gray"><em>PostgreSQL:</em></span><br />
select array_upper(a, 1) from foo;</td>
<td><span style="color: gray"><em>none, but</em> split <em>function returns length</em></span></td>
<td>bar = FOREACH foo GENERATE SIZE(a);</td>
</tr>
<tr>
<td><a name="array-lookup"></a><a href="#array-lookup-note">lookup</a></td>
<td><span style="color: gray"><em>PostgreSQL:</em></span><br />
select a[1] from foo;</td>
<td>a[0]</td>
<td>bar = FOREACH foo GENERATE a.$0;</td>
</tr>
<tr>
<td><a name="array-update"></a><a href="#array-update-note">update</a></td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="array-iteration"></a><a href="#array-iteration-note">iteration</a></td>
<td> </td>
<td>for (i in a) print i, a[i]</td>
<td> </td>
</tr>
<tr>
<td><a name="membership"></a><a href="#membership-note">membership</a></td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<th colspan="4"><a name="dictionaries"></a><a href="#dictionaries-note">dictionaries</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="dictionary-literal"></a><a href="#dictionary-literal-note">literal</a></td>
<td> </td>
<td> </td>
<td>['t'#1, 'f'#0]</td>
</tr>
<tr>
<th colspan="4"><a name="tables"></a><a href="#tables-note">tables</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="order-by"></a><a href="#order-by-note">order rows by column</a></td>
<td><span style="color: gray"><em>ordering depends on type of column</em></span><br />
select name<br />
from pwt<br />
order by name;</td>
<td><span style="color: gray"><em>ordering is lexical unless</em> -n <em>flag is used</em></span><br />
$ sort -k1 -t: /etc/passwd</td>
<td>names = foreach pwf generate name;<br />
ordered_names = order names by name;</td>
</tr>
<tr>
<td><a name="order-by-multiple"></a><a href="#order-by-multiple-note">order rows by multiple columns</a></td>
<td>select group, name<br />
from pwt<br />
order by group, name;</td>
<td> </td>
<td> </td>
</tr>
<tr>
<td>order rows in descending order</td>
<td>select name<br />
from pwt<br />
order by name;</td>
<td>$ sort -k1 -r -t: /etc/passwd</td>
<td> </td>
</tr>
<tr>
<td><a name="limit"></a><a href="#limit-note">limit</a></td>
<td>select name from pwt order by name limit 10;</td>
<td> </td>
<td>first_ten = limit ordered_names 10;</td>
</tr>
<tr>
<td><a name="offset"></a><a href="#offset-note">offset</a></td>
<td>select name from pwt order by name limit 10 offset 10;</td>
<td> </td>
<td> </td>
</tr>
<tr>
<th colspan="4"><a name="relational-algebra"></a><a href="#relational-algebra-note">relational algebra</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="poject-column-by-name"></a><a href="#project-column-by-name-note">project columns by name</a></td>
<td>select name, pw from pwt;</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>name_pw = foreach pwf generate name, pw;</td>
</tr>
<tr>
<td><a name="project-column-by-position"></a><a href="#project-column-by-position-note">project columns by position</a></td>
<td><span style="color: gray"><em>none</em></span></td>
<td>{ print $1, $2 }</td>
<td>name_pw = foreach pwf generate $0, $1;</td>
</tr>
<tr>
<td><a name="project-expr"></a><a href="#project-expr-note">project expression</a></td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="project-all-columns"></a><a href="#project-all-columns-note">project all columns</a></td>
<td>select * from pwt;</td>
<td><span style="color: gray"># prints input line:</span><br />
{ print $0 }</td>
<td>pwf2 = foreach pwf generate *;</td>
</tr>
<tr>
<td><a name="rename-columns"></a><a href="#rename-columns-note">rename columns</a></td>
<td>select uid as userid, gid as groupid<br />
from pwf;</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>usergroups = foreach pwf generate uid as userid, gid as groupid;</td>
</tr>
<tr>
<td><a name="select-rows"></a><a href="#select-rows-note">select rows</a></td>
<td>select * from pwt where name = 'root';</td>
<td>$1 == "root" { print $0 }</td>
<td>pwf3 = filter pwf by name == 'root';</td>
</tr>
<tr>
<td><a name="select-distinct-rows"></a><a href="#select-distinct-rows-note">select distinct rows</a></td>
<td>select distinct gid from pwt;</td>
<td>$ cat > gid.awk<br />
BEGIN { FS=":" }<br />
!/^#/ { print $4 }<br />
$ awk -f gid.awk /etc/passwd > /tmp/x<br />
$ sort -u /tmp/x</td>
<td>gids1 = foreach pwf generate gid;<br />
gids2 = distinct gids1;</td>
</tr>
<tr>
<td><a name="split-rows"></a><a href="#split-rows-note">split rows</a></td>
<td> </td>
<td> </td>
<td>split pwf into rootpwf if name == 'root', otherpwf if name != 'root';</td>
</tr>
<tr>
<td><a name="inner-join"></a><a href="#inner-join-note">inner join</a></td>
<td>create temp table gt (<br />
<span style="white-space: pre-wrap;"> </span>name text, pw text,<br />
<span style="white-space: pre-wrap;"> </span>gid int, members text<br />
);<br />
<br />
copy gt from '/etc/group'<br />
with delimiter ':';<br />
<br />
select * from pwt<br />
join gt on pwt.gid = gt.gid;</td>
<td>$ awk '!/^#/' /etc/passwd > /tmp/x<br />
$ sort -k4,4 -t: < /tmp/x > /tmp/pw<br />
<br />
$ awk '!/^#/' /etc/group > /tmp/y<br />
$ sort -k3,3 -t: < /tmp/y > /tmp/g<br />
<br />
$ join -t: -14 -23 /tmp/pw /tmp/g</td>
<td>gf = load '/etc/group' using PigStorage(':') as (name:chararray, pw:chararray, gid:int, members:chararray);<br />
<br />
pwgf = join pwf by gid, gf by gid;</td>
</tr>
<tr>
<td><a name="nulls-as-join-values"></a><a href="#nulls-as-join-values-note">nulls as join values</a></td>
<td><span style="color: gray"><em>input tuples with nulls for join values are omitted from inner joins</em></span></td>
<td><span style="color: gray"><em>no null value; empty strings are joinable values</em></span></td>
<td><span style="color: gray"><em>input tuples with nulls for join values are omitted from inner joins</em></span></td>
</tr>
<tr>
<td><a name="self-join"></a><a href="#self-join-note">self join</a></td>
<td>select pwt1.name, pwt2.name<br />
from pwt as pwt1, pwt as pwt2<br />
where pwt1.gid = pwt2.gid;</td>
<td>$ join -t: -14 -24 /tmp/pw /tmp/pw</td>
<td>pwf2 = foreach pwf generate *;<br />
joined_by_gid = join pwf by gid, pwf2 by gid;<br />
name_pairs = foreach by_group generate pwf::name, pwf2::name;</td>
</tr>
<tr>
<td><a name="left-join"></a><a href="#left-join-note">left join</a></td>
<td>select *<br />
from customers c<br />
left join orders o<br />
<span style="white-space: pre-wrap;"> </span>on c.id = o.customer_id;</td>
<td>$ join -t: -a1 -11 -22 /tmp/c /tmp/o</td>
<td>j = join customers by id left, orders by customer_id;</td>
</tr>
<tr>
<td><a name="outer-join"></a><a href="#full-join-note">full join</a></td>
<td>select *<br />
from customers c<br />
full join orders o<br />
<span style="white-space: pre-wrap;"> </span>on c.id = o.customer_id;</td>
<td>$ join -t: -a1 -a2 -11 -22 /tmp/c /tmp/o</td>
<td>j = join customers by id full, orders by customer_id;</td>
</tr>
<tr>
<td><a name="antijoin"></a><a href="#antijoin-note">antijoin</a></td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="cross-join"></a><a href="#cross-join-note">cross join</a></td>
<td>create table files ( file text );<br />
insert into files values ('a'), ('b'), ('c'), ('d'), ('e'), ('f'), ('g'), ('h');<br />
<br />
create table ranks ( rank int );<br />
insert into ranks values (1), (2), (3), (4), (5), (6), (7), (8);<br />
<br />
create table chessboard ( file text, rank int );<br />
insert into chessboard<br />
select *<br />
from files, ranks;</td>
<td><span style="color: gray"><em>specify nonexistent join fields:</em></span><br />
<br />
$ join -12 -22 /tmp/f /tmp/r</td>
<td>files = load '/tmp/files.txt' as (file:chararray);<br />
<br />
ranks = load '/tmp/ranks.txt' as (rank:int);<br />
<br />
chessboard = cross files, ranks;</td>
</tr>
<tr>
<th colspan="4"><a name="aggregation"></a><a href="#aggregation-note">aggregation</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="group-by"></a><a href="#group-by-note">group by</a></td>
<td>select gid, count(*)<br />
from pwf<br />
group by gid;</td>
<td>BEGIN { FS=":" }<br />
!/^#/ { cnt[$4]++ }<br />
END { for (i in cnt) print i, cnt[i] }</td>
<td>by_group = group pwf by gid;<br />
cnts = foreach by_group generate $0, COUNT($1);</td>
</tr>
<tr>
<td><a name="group-by-multiple"></a><a href="#group-by-multiple-note">group by multiple columns</a></td>
<td>select gid, sh, count(*)<br />
from pwf<br />
group by gid, sh;</td>
<td> </td>
<td>by_group = group pwf by (gid, sh);<br />
cnts = foreach by_group generate FLATTEN($0), COUNT($1);</td>
</tr>
<tr>
<td><a name="aggregation-func"></a><a href="#aggregation-func-note">aggregation functions</a></td>
<td>count sum min max avg stddev</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>COUNT SUM MIN MAX AVG <span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<th colspan="4"><a name="functions"></a><a href="#functions-note">functions</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">pl/sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="def-func"></a><a href="#def-func-note">define function</a></td>
<td>create or replace function<br />
<span style="white-space: pre-wrap;"> </span>add ( x int, y int )<br />
<span style="white-space: pre-wrap;"> </span>returns int as $$<br />
begin<br />
<span style="white-space: pre-wrap;"> </span>return x + y;<br />
end; $$ language plpgsql;</td>
<td><span style="color: gray"><em>can be defined at position of pattern-action statement:</em></span><br />
<br />
function add(x, y) { return x+y }</td>
<td><span style="color: gray"><em>in</em> org/hpglot/Add.java:</span><br />
package org.hpglot;<br />
<br />
import java.io.IOException;<br />
import org.apache.pig.EvalFunc;<br />
import org.apache.pig.data.Tuple;<br />
<br />
public class Add extends EvalFunc<Integer> {<br />
<span style="white-space: pre-wrap;"> </span>@Override public Integer<br />
<span style="white-space: pre-wrap;"> </span>exec(Tuple input) throws IOException {<br />
<span style="white-space: pre-wrap;"> </span><span style="white-space: pre-wrap;"> </span>Integer x, y;<br />
<span style="white-space: pre-wrap;"> </span><span style="white-space: pre-wrap;"> </span>if (input == null @@</td>
</tr>
<tr>
<td><a name="invoke-func"></a><a href="#invoke-func-note">invoke function</a></td>
<td>select add(x, y) from foo;</td>
<td>{ print add($1, $2) }</td>
<td>REGISTER Add.jar<br />
DEFINE ADD org.hpglot.Add();<br />
<br />
foo = LOAD 'foo.txt' AS (x:int, y:int);<br />
bar = FOREACH foo GENERATE ADD(x, y);</td>
</tr>
<tr>
<td><a name="drop-func"></a><a href="#drop-func-note">drop function</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>drop function add(integer, integer);</td>
<td><span style="color: gray"><em>none</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<th colspan="4"><a name="execution-control"></a><a href="#execution-control-note">execution control</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">pl/sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="if"></a><a href="#if-note">if</a></td>
<td> </td>
<td>if (!0) print "foo"; else print "bar"</td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="while"></a><a href="#while-note">while</a></td>
<td> </td>
<td>i = 0; while (i<5) print i++</td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<td><a name="for"></a><a href="#for-note">for</a></td>
<td> </td>
<td>for (i=0; i<5; i++) print i</td>
<td><span style="color: gray"><em>none</em></span></td>
</tr>
<tr>
<th colspan="4"><a name="files"></a><a href="#files-note">files</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="field-delimiter"></a><a href="#field-delimiter-note">set field delimiter</a></td>
<td>$ grep -v '^#' /etc/passwd > /tmp/pw<br />
<br />
create table pwt ( name text, pw text, uid int, gid int, gecos text, home text, sh text );<br />
<br />
copy pwt from '/tmp/pw' with delimiter ':';</td>
<td>BEGIN { FS=":" }</td>
<td>pwf = LOAD '/etc/passwd' USING PigStorage(':') AS (name:chararray, pw:chararray, uid:int, gid:int, gecos:chararray, home:chararray, sh:chararray);</td>
</tr>
<tr>
<td><a name="write-table-file"></a><a href="#write-table-file-note">write table to file</a></td>
<td> </td>
<td> </td>
<td>STORE foo INTO '/tmp/foo.tab';</td>
</tr>
<tr>
<th colspan="4"><a name="libraries-namespaces"></a><a href="#libraries-namespaces-note">libraries and namespaces</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<th colspan="4"><a name="reflection"></a><a href="#reflection-note">reflection</a></th>
</tr>
<tr>
<th></th>
<th><a href="#sql">sql</a></th>
<th><a href="#awk">awk</a></th>
<th><a href="#pig">pig</a></th>
</tr>
<tr>
<td><a name="table-schema"></a><a href="#table-schema-note">table schema</a></td>
<td> </td>
<td> </td>
<td>DESCRIBE foo;</td>
</tr>
<tr>
<th></th>
<th><span style="color: #efefef"><span style="white-space: pre-wrap;">_________________________________________</span></span></th>
<th><span style="color: #efefef"><span style="white-space: pre-wrap;">_________________________________________</span></span></th>
<th><span style="color: #efefef"><span style="white-space: pre-wrap;">_________________________________________</span></span></th>
</tr>
</table>
<p><a name="general-note"></a></p>
<h1 id="toc0"><span><a href="#general">General</a></span></h1>
<p><a name="version-used-note"></a></p>
<h2 id="toc1"><span><a href="#version-used">versions used</a></span></h2>
<p>The versions used for testing code in the reference sheet.</p>
<p><a name="show-version-note"></a></p>
<h2 id="toc2"><span><a href="#show-version">show version</a></span></h2>
<p>How to get the version.</p>
<p><a name="grammar-invocation-note"></a></p>
<h1 id="toc3"><span><a href="#grammar-invocation">Grammar and Invocation</a></span></h1>
<p><a name="interpreter-note"></a></p>
<h2 id="toc4"><span><a href="#interpreter">interpreter</a></span></h2>
<p>How to run the interpreter on a script.</p>
<p><a name="repl-note"></a></p>
<h2 id="toc5"><span><a href="#repl">repl</a></span></h2>
<p>How to invoke the REPL.</p>
<p><a name="statement-separator-note"></a></p>
<h2 id="toc6"><span><a href="#statement-separator">statement separator</a></span></h2>
<p>The statement separator.</p>
<p><a name="block-delimiters-note"></a></p>
<h2 id="toc7"><span><a href="#block-delimiters">block delimiters</a></span></h2>
<p>The delimiters used for blocks.</p>
<p><a name="eol-comment-note"></a></p>
<h2 id="toc8"><span><a href="#eol-comment">end-of-line comment</a></span></h2>
<p>How to create a comment that ends at the next newline.</p>
<p><a name="multiple-line-comment-note"></a></p>
<h2 id="toc9"><span><a href="#multiple-line-comment">multiple line comment</a></span></h2>
<p>How to comment out multiple lines.</p>
<p><a name="var-expr-note"></a></p>
<h1 id="toc10"><span><a href="#var-expr">Variables and Expressions</a></span></h1>
<p><a name="case-sensitive-note"></a></p>
<h2 id="toc11"><span><a href="#case-sensitive">case sensitive?</a></span></h2>
<p>Are identifiers which differ only by case treated as distinct identifiers?</p>
<p><a name="quoted-id-note"></a></p>
<h2 id="toc12"><span><a href="#quoted-id">quoted identifier</a></span></h2>
<p>How to quote an identifier.</p>
<p>Quoting an identifier is a way to include characters which aren't normally permitted in an identifier.</p>
<p>In SQL quoting is also a way to refer to an identifier that would otherwise be interpreted as a reserved word</p>
<p><a name="null-note"></a></p>
<h2 id="toc13"><span><a href="#null">null</a></span></h2>
<p>The null literal.</p>
<p><strong>pig:</strong></p>