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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Functions and Operators</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 9.2.24 Documentation" HREF="index.html"><LINK REL="UP" TITLE="The SQL Language" HREF="sql.html"><LINK REL="PREVIOUS" TITLE="Pseudo-Types" HREF="datatype-pseudo.html"><LINK REL="NEXT" TITLE="Logical Operators" HREF="functions-logical.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2017-11-06T22:43:11"></HEAD ><BODY CLASS="CHAPTER" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.2.24 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="Pseudo-Types" HREF="datatype-pseudo.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="Logical Operators" HREF="functions-logical.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="FUNCTIONS" ></A >Chapter 9. Functions and Operators</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >9.1. <A HREF="functions-logical.html" >Logical Operators</A ></DT ><DT >9.2. <A HREF="functions-comparison.html" >Comparison Operators</A ></DT ><DT >9.3. <A HREF="functions-math.html" >Mathematical Functions and Operators</A ></DT ><DT >9.4. <A HREF="functions-string.html" >String Functions and Operators</A ></DT ><DT >9.5. <A HREF="functions-binarystring.html" >Binary String Functions and Operators</A ></DT ><DT >9.6. <A HREF="functions-bitstring.html" >Bit String Functions and Operators</A ></DT ><DT >9.7. <A HREF="functions-matching.html" >Pattern Matching</A ></DT ><DD ><DL ><DT >9.7.1. <A HREF="functions-matching.html#FUNCTIONS-LIKE" ><CODE CLASS="FUNCTION" >LIKE</CODE ></A ></DT ><DT >9.7.2. <A HREF="functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP" ><CODE CLASS="FUNCTION" >SIMILAR TO</CODE > Regular Expressions</A ></DT ><DT >9.7.3. <A HREF="functions-matching.html#FUNCTIONS-POSIX-REGEXP" ><ACRONYM CLASS="ACRONYM" >POSIX</ACRONYM > Regular Expressions</A ></DT ></DL ></DD ><DT >9.8. <A HREF="functions-formatting.html" >Data Type Formatting Functions</A ></DT ><DT >9.9. <A HREF="functions-datetime.html" >Date/Time Functions and Operators</A ></DT ><DD ><DL ><DT >9.9.1. <A HREF="functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT" ><CODE CLASS="FUNCTION" >EXTRACT</CODE >, <CODE CLASS="FUNCTION" >date_part</CODE ></A ></DT ><DT >9.9.2. <A HREF="functions-datetime.html#FUNCTIONS-DATETIME-TRUNC" ><CODE CLASS="FUNCTION" >date_trunc</CODE ></A ></DT ><DT >9.9.3. <A HREF="functions-datetime.html#FUNCTIONS-DATETIME-ZONECONVERT" ><TT CLASS="LITERAL" >AT TIME ZONE</TT ></A ></DT ><DT >9.9.4. <A HREF="functions-datetime.html#FUNCTIONS-DATETIME-CURRENT" >Current Date/Time</A ></DT ><DT >9.9.5. <A HREF="functions-datetime.html#FUNCTIONS-DATETIME-DELAY" >Delaying Execution</A ></DT ></DL ></DD ><DT >9.10. <A HREF="functions-enum.html" >Enum Support Functions</A ></DT ><DT >9.11. <A HREF="functions-geometry.html" >Geometric Functions and Operators</A ></DT ><DT >9.12. <A HREF="functions-net.html" >Network Address Functions and Operators</A ></DT ><DT >9.13. <A HREF="functions-textsearch.html" >Text Search Functions and Operators</A ></DT ><DT >9.14. <A HREF="functions-xml.html" >XML Functions</A ></DT ><DD ><DL ><DT >9.14.1. <A HREF="functions-xml.html#FUNCTIONS-PRODUCING-XML" >Producing XML Content</A ></DT ><DT >9.14.2. <A HREF="functions-xml.html#FUNCTIONS-XML-PREDICATES" >XML Predicates</A ></DT ><DT >9.14.3. <A HREF="functions-xml.html#FUNCTIONS-XML-PROCESSING" >Processing XML</A ></DT ><DT >9.14.4. <A HREF="functions-xml.html#FUNCTIONS-XML-MAPPING" >Mapping Tables to XML</A ></DT ></DL ></DD ><DT >9.15. <A HREF="functions-json.html" >JSON Functions</A ></DT ><DT >9.16. <A HREF="functions-sequence.html" >Sequence Manipulation Functions</A ></DT ><DT >9.17. <A HREF="functions-conditional.html" >Conditional Expressions</A ></DT ><DD ><DL ><DT >9.17.1. <A HREF="functions-conditional.html#FUNCTIONS-CASE" ><TT CLASS="LITERAL" >CASE</TT ></A ></DT ><DT >9.17.2. <A HREF="functions-conditional.html#FUNCTIONS-COALESCE-NVL-IFNULL" ><TT CLASS="LITERAL" >COALESCE</TT ></A ></DT ><DT >9.17.3. <A HREF="functions-conditional.html#FUNCTIONS-NULLIF" ><TT CLASS="LITERAL" >NULLIF</TT ></A ></DT ><DT >9.17.4. <A HREF="functions-conditional.html#FUNCTIONS-GREATEST-LEAST" ><TT CLASS="LITERAL" >GREATEST</TT > and <TT CLASS="LITERAL" >LEAST</TT ></A ></DT ></DL ></DD ><DT >9.18. <A HREF="functions-array.html" >Array Functions and Operators</A ></DT ><DT >9.19. <A HREF="functions-range.html" >Range Functions and Operators</A ></DT ><DT >9.20. <A HREF="functions-aggregate.html" >Aggregate Functions</A ></DT ><DT >9.21. <A HREF="functions-window.html" >Window Functions</A ></DT ><DT >9.22. <A HREF="functions-subquery.html" >Subquery Expressions</A ></DT ><DD ><DL ><DT >9.22.1. <A HREF="functions-subquery.html#FUNCTIONS-SUBQUERY-EXISTS" ><TT CLASS="LITERAL" >EXISTS</TT ></A ></DT ><DT >9.22.2. <A HREF="functions-subquery.html#FUNCTIONS-SUBQUERY-IN" ><TT CLASS="LITERAL" >IN</TT ></A ></DT ><DT >9.22.3. <A HREF="functions-subquery.html#FUNCTIONS-SUBQUERY-NOTIN" ><TT CLASS="LITERAL" >NOT IN</TT ></A ></DT ><DT >9.22.4. <A HREF="functions-subquery.html#FUNCTIONS-SUBQUERY-ANY-SOME" ><TT CLASS="LITERAL" >ANY</TT >/<TT CLASS="LITERAL" >SOME</TT ></A ></DT ><DT >9.22.5. <A HREF="functions-subquery.html#FUNCTIONS-SUBQUERY-ALL" ><TT CLASS="LITERAL" >ALL</TT ></A ></DT ><DT >9.22.6. <A HREF="functions-subquery.html#AEN18263" >Row-wise Comparison</A ></DT ></DL ></DD ><DT >9.23. <A HREF="functions-comparisons.html" >Row and Array Comparisons</A ></DT ><DD ><DL ><DT >9.23.1. <A HREF="functions-comparisons.html#AEN18300" ><TT CLASS="LITERAL" >IN</TT ></A ></DT ><DT >9.23.2. <A HREF="functions-comparisons.html#AEN18316" ><TT CLASS="LITERAL" >NOT IN</TT ></A ></DT ><DT >9.23.3. <A HREF="functions-comparisons.html#AEN18338" ><TT CLASS="LITERAL" >ANY</TT >/<TT CLASS="LITERAL" >SOME</TT > (array)</A ></DT ><DT >9.23.4. <A HREF="functions-comparisons.html#AEN18361" ><TT CLASS="LITERAL" >ALL</TT > (array)</A ></DT ><DT >9.23.5. <A HREF="functions-comparisons.html#ROW-WISE-COMPARISON" >Row-wise Comparison</A ></DT ></DL ></DD ><DT >9.24. <A HREF="functions-srf.html" >Set Returning Functions</A ></DT ><DT >9.25. <A HREF="functions-info.html" >System Information Functions</A ></DT ><DT >9.26. <A HREF="functions-admin.html" >System Administration Functions</A ></DT ><DD ><DL ><DT >9.26.1. <A HREF="functions-admin.html#FUNCTIONS-ADMIN-SET" >Configuration Settings Functions</A ></DT ><DT >9.26.2. <A HREF="functions-admin.html#FUNCTIONS-ADMIN-SIGNAL" >Server Signalling Functions</A ></DT ><DT >9.26.3. <A HREF="functions-admin.html#FUNCTIONS-ADMIN-BACKUP" >Backup Control Functions</A ></DT ><DT >9.26.4. <A HREF="functions-admin.html#FUNCTIONS-RECOVERY-CONTROL" >Recovery Control Functions</A ></DT ><DT >9.26.5. <A HREF="functions-admin.html#FUNCTIONS-SNAPSHOT-SYNCHRONIZATION" >Snapshot Synchronization Functions</A ></DT ><DT >9.26.6. <A HREF="functions-admin.html#FUNCTIONS-ADMIN-DBOBJECT" >Database Object Management Functions</A ></DT ><DT >9.26.7. <A HREF="functions-admin.html#FUNCTIONS-ADMIN-GENFILE" >Generic File Access Functions</A ></DT ><DT >9.26.8. <A HREF="functions-admin.html#FUNCTIONS-ADVISORY-LOCKS" >Advisory Lock Functions</A ></DT ></DL ></DD ><DT >9.27. <A HREF="functions-trigger.html" >Trigger Functions</A ></DT ></DL ></DIV ><P > <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > provides a large number of functions and operators for the built-in data types. Users can also define their own functions and operators, as described in <A HREF="server-programming.html" >Part V</A >. The <SPAN CLASS="APPLICATION" >psql</SPAN > commands <TT CLASS="COMMAND" >\df</TT > and <TT CLASS="COMMAND" >\do</TT > can be used to list all available functions and operators, respectively. </P ><P > If you are concerned about portability then note that most of the functions and operators described in this chapter, with the exception of the most trivial arithmetic and comparison operators and some explicitly marked functions, are not specified by the <ACRONYM CLASS="ACRONYM" >SQL</ACRONYM > standard. Some of this extended functionality is present in other <ACRONYM CLASS="ACRONYM" >SQL</ACRONYM > database management systems, and in many cases this functionality is compatible and consistent between the various implementations. This chapter is also not exhaustive; additional functions appear in relevant sections of the manual. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="datatype-pseudo.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="functions-logical.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Pseudo-Types</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="sql.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Logical Operators</TD ></TR ></TABLE ></DIV ></BODY ></HTML >