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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>SQLite Query Language: Core Functions</title><style type="text/css">body {    margin: auto;    font-family: "Verdana" "sans-serif";    padding: 8px 1%;}a { color: #45735f }a:visited { color: #734559 }.logo { position:absolute; margin:3px; }.tagline {  float:right;  text-align:right;  font-style:italic;  width:240px;  margin:12px;  margin-top:58px;}.toolbar {  font-variant: small-caps;  text-align: center;  line-height: 1.6em;  margin: 0;  padding:1px 8px;}.toolbar a { color: white; text-decoration: none; padding: 6px 12px; }.toolbar a:visited { color: white; }.toolbar a:hover { color: #80a796; background: white; }.content    { margin: 5%; }.content dt { font-weight:bold; }.content dd { margin-bottom: 25px; margin-left:20%; }.content ul { padding:0px; padding-left: 15px; margin:0px; }/* rounded corners */.se  { background: url(images/se.png) 100% 100% no-repeat #80a796}.sw  { background: url(images/sw.png) 0% 100% no-repeat }.ne  { background: url(images/ne.png) 100% 0% no-repeat }.nw  { background: url(images/nw.png) 0% 0% no-repeat }</style><meta http-equiv="content-type" content="text/html; charset=UTF-8">  </head><body><div><!-- container div to satisfy validator --><a href="index.html"><img class="logo" src="images/SQLite.gif" alt="SQLite Logo" border="0"></a><div><!-- IE hack to prevent disappearing logo--></div><div class="tagline">Small. Fast. Reliable.<br>Choose any three.</div><table width=100% style="clear:both"><tr><td>  <div class="se"><div class="sw"><div class="ne"><div class="nw">  <div class="toolbar">    <a href="about.html">About</a>    <a href="sitemap.html">Sitemap</a>    <a href="docs.html">Documentation</a>    <a href="download.html">Download</a>    <a href="copyright.html">License</a>    <a href="news.html">News</a>    <a href="http://www.sqlite.org/cvstrac/index">Developers</a>    <a href="support.html">Support</a>  </div></div></div></div></div></td></tr></table>  <a href="lang.html"><h2>SQL As Understood By SQLite</h2></a><h3>Core Functions</h3><p>The core functions shown below are available by default.  Additionalfunctions may be written in C and added to the database engine usingthe <a href="c3ref/create_function.html">sqlite3_create_function()</a> API.</p><table border=0 cellpadding=10><tr><td valign="top" align="right" width="120">abs(<i>X</i>)</td><td valign="top"><a name="abs"></a>  Return the absolute value of the numeric  argument <i>X</i>.  Return NULL if <i>X</i> is NULL.  Return 0.0 if  <i>X</i> is not a numeric value.</td></tr><tr><td valign="top" align="right" width="120">coalesce(<i>X</i>,<i>Y</i>,...)</td><td valign="top"><a name="coalesce"></a>  Return a copy of the first non-NULL argument.  If  all arguments are NULL then NULL is returned.  There must be at least   2 arguments.</td></tr><tr><td valign="top" align="right" width="120">glob(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="glob"></a>  This function is used to implement the  "<b>X GLOB Y</b>" syntax of SQLite.  The <a href="c3ref/create_function.html">sqlite3_create_function()</a>  interface can  be used to override this function and thereby change the operation  of the <a href="lang_expr.html#glob">GLOB</a> operator.</td></td></tr><tr><td valign="top" align="right" width="120">ifnull(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="ifnull"></a>  Return a copy of the first non-NULL argument.  If  both arguments are NULL then NULL is returned. This behaves the same as   <a href="lang_corefunc.html#coalesce">coalesce()</a>.</td></td></tr><tr><td valign="top" align="right" width="120">hex(<i>X</i>)</td><td valign="top"><a name="hex"></a>  The argument is interpreted as a BLOB.  The result  is a hexadecimal rendering of the content of that blob.</td></tr><tr><td valign="top" align="right" width="120">last_insert_rowid()</td><td valign="top"><a name="last_insert_rowid"></a>  Return the <a href="lang_createtable.html#rowid">ROWID</a>  of the last row insert from this  connection to the database.   This is the same value that would be returned  from the <a href="c3ref/last_insert_rowid.html">sqlite3_last_insert_rowid()</a> API function.</td></tr><tr><td valign="top" align="right" width="120">length(<i>X</i>)</td><td valign="top"><a name="length"></a>  Return the string length of <i>X</i> in characters.  If SQLite is configured to support UTF-8, then the number of UTF-8  characters is returned, not the number of bytes.</td></tr><tr><td valign="top" align="right" width="120">like(<i>X</i>,<i>Y</i>)<br></br>like(<i>X</i>,<i>Y</i>,<i>Z</i>)</td><td valign="top"><a name="like"></a>  This function is used to implement the "<b>X LIKE Y &#91;ESCAPE Z&#93;</b>"  syntax of SQL. If the optional ESCAPE clause is present, then the  user-function is invoked with three arguments. Otherwise, it is  invoked with two arguments only. The   <a href="c3ref/create_function.html">sqlite3_create_function()</a> interface can be used to override this  function and thereby change the operation of the  <a href="lang_expr.html#like">LIKE</a> operator. When doing this, it may be important  to override both the two and three argument versions of the like()   function. Otherwise, different code may be called to implement the  <a href="lang_expr.html#like">LIKE</a> operator depending on whether or not an ESCAPE clause was   specified.</td></tr><tr><td valign="top" align="right" width="120">load_extension(<i>X</i>)<br></br>load_extension(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="load_extension"></a>  Load SQLite extensions out of the shared library  file named <i>X</i> using the entry point <i>Y</i>.  The result  is a NULL.  If <i>Y</i> is omitted then the default entry point  of <b>sqlite3_extension_init</b> is used.  This function raises  an exception if the extension fails to load or initialize correctly.  <p>This function will fail if the extension attempts to modify  or delete a SQL function or collating sequence.  The  extension can add new functions or collating sequences, but cannot  modify or delete existing functions or collating sequences because  those functions and/or collating sequences might be used elsewhere  in the currently running SQL statement.  To load an extension that  changes or deletes functions or collating sequences, use the  <a href="c3ref/load_extension.html">sqlite3_load_extension()</a> C-language API.</p></td></tr><tr><td valign="top" align="right" width="120">lower(<i>X</i>)</td><td valign="top"><a name="lower"></a>  Return a copy of string <i>X</i> will all ASCII characters  converted to lower case.  The C library <b>tolower()</b> routine is used  for the conversion, which means that this function might not  work correctly on non-ASCII UTF-8 characters.</td></tr><tr><td valign="top" align="right" width="120">ltrim(<i>X</i>)<br></br>ltrim(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="ltrim"></a>  Return a string formed by removing any and all  characters that appear in <i>Y</i> from the left side of <i>X</i>.  If the <i>Y</i> argument is omitted, spaces are removed.</td></tr><tr><td valign="top" align="right" width="120">max(<i>X</i>,<i>Y</i>,...)</td><td valign="top"><a name="maxCoreFunc"></a>  Return the argument with the maximum value.  Arguments  may be strings in addition to numbers.  The maximum value is determined  by the usual sort order.  Note that <b>max()</b> is a simple function when  it has 2 or more arguments but converts to an aggregate function if given  only a single argument.</td></tr><tr><td valign="top" align="right" width="120">min(<i>X</i>,<i>Y</i>,...)</td><td valign="top"><a name="minCoreFunc"></a>  Return the argument with the minimum value.  Arguments  may be strings in addition to numbers.  The minimum value is determined  by the usual sort order.  Note that <b>min()</b> is a simple function when  it has 2 or more arguments but converts to an aggregate function if given  only a single argument.</td></tr><tr><td valign="top" align="right" width="120">nullif(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="nullif"></a>  Return the first argument if the arguments are different,   otherwise return NULL.</td></tr><tr><td valign="top" align="right" width="120">quote(<i>X</i>)</td><td valign="top"><a name="quote"></a>  This routine returns a string which is the value of  its argument suitable for inclusion into another SQL statement.  Strings are surrounded by single-quotes with escapes on interior quotes  as needed.  BLOBs are encoded as hexadecimal literals.  The implementation of <a href="lang_vacuum.html">VACUUM</a> uses this function. The function  is also useful when writing triggers to implement undo/redo functionality.</td></tr><tr><td valign="top" align="right" width="120">random()</td><td valign="top"><a name="random"></a>  Return a pseudo-random integer  between -9223372036854775808 and +9223372036854775807.</td></tr><tr><td valign="top" align="right" width="120">randomblob(<i>N</i>)</td><td valign="top"><a name="randomblob"></a>  Return an <i>N</i>-byte blob containing pseudo-random bytes.  <i>N</i> should be a postive integer.  <p>Hint:  applications can generate globally unique identifiers  using this function together with <a href="lang_corefunc.html#hex">hex()</a> and/or  <a href="lang_corefunc.html#lower">lower()</a> like this:</p>  <blockquote>  hex(randomblob(16))<br></br>  lower(hex(randomblob(16)))  </blockquote></td></tr><tr><td valign="top" align="right" width="120">replace(<i>X</i>,<i>Y</i>,<i>Z</i>)</td><td valign="top"><a name="replace"></a>  Return a string formed by substituting string <i>Z</i> for  every occurrance of string <i>Y</i> in string <i>X</i>.  The <a href="datatype3.html#collation">BINARY</a>  collating sequence is used for comparisons.</td></tr><tr><td valign="top" align="right" width="120">round(<i>X</i>)<br></br>round(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="round"></a>  Round off the number <i>X</i> to <i>Y</i> digits to the  right of the decimal point.  If the <i>Y</i> argument is omitted, 0 is   assumed.</td></tr><tr><td valign="top" align="right" width="120">rtrim(<i>X</i>)<br></br>rtrim(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="rtrim"></a>  Return a string formed by removing any and all  characters that appear in <i>Y</i> from the right side of <i>X</i>.  If the <i>Y</i> argument is omitted, spaces are removed.</td></tr><tr><td valign="top" align="right" width="120">soundex(<i>X</i>)</td><td valign="top"><a name="soundex"></a>  Compute the soundex encoding of the string <i>X</i>.  The string "?000" is returned if the argument is NULL.  This function is omitted from SQLite by default.  It is only available the -DSQLITE_SOUNDEX=1 compiler option  is used when SQLite is built.</td></tr><tr><td valign="top" align="right" width="120">sqlite_version(<i>X</i>)</td><td valign="top"><a name="sqlite_version"></a>  Return the version string for the SQLite library  that is running.  Example:  "3.5.9"</td></tr><tr><td valign="top" align="right" width="120">substr(<i>X</i>,<i>Y</i>,<i>Z</i>)<br></br>substr(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="substr"></a>  Return a substring of input string <i>X</i> that begins  with the <i>Y</i>-th character and which is <i>Z</i> characters long.  If <i>Z</i> is omitted then all character through the end of the string  are returned.  The left-most character of <i>X</i> is number 1.  If <i>Y</i> is negative  the the first character of the substring is found by counting from the  right rather than the left.  If <i>X</i> is string  then characters indices refer to actual UTF-8 characters.  If  <i>X</i> is a BLOB then the indices refer to bytes.</td></tr><tr><td valign="top" align="right" width="120">trim(<i>X</i>)<br></br>trim(<i>X</i>,<i>Y</i>)</td><td valign="top"><a name="trim"></a>  Return a string formed by removing any and all  characters that appear in <i>Y</i> from both ends of <i>X</i>.  If the <i>Y</i> argument is omitted, spaces are removed.</td></tr><tr><td valign="top" align="right" width="120">typeof(<i>X</i>)</td><td valign="top"><a name="typeof"></a>  Return the type of the expression <i>X</i>.  The only   return values are "null", "integer", "real", "text", and "blob".  SQLite's type handling is   explained in <a href="datatype3.html">Datatypes in SQLite Version 3</a>.</td></tr><tr><td valign="top" align="right" width="120">upper(<i>X</i>)</td><td valign="top"><a name="upper"></a>  Return a copy of input string <i>X</i> converted to all  upper-case letters.  The implementation of this function uses the C library  routine <b>toupper()</b> which means it may not work correctly on   non-ASCII UTF-8 strings.</td></tr><tr><td valign="top" align="right" width="120">zeroblob(<i>N</i>)</td><td valign="top"><a name="zeroblob"></a>  Return a BLOB consisting of N bytes of 0x00.  SQLite  manages these zeroblobs very efficiently.  Zeroblobs can be used to  reserve space for a BLOB that is later written using   <a href="c3ref/blob_open.html">incremental BLOB I/O</a>.</td></tr></table><hr><small><i>This page last modified 2008/04/27 17:48:52 UTC</i></small></div></body></html>
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