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<td valign="top" align="right">max(<i>X</i>,<i>Y</i>,...)</td>
<td valign="top">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>
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<td valign="top" align="right">min(<i>X</i>,<i>Y</i>,...)</td>
<td valign="top">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>
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<td valign="top" align="right">nullif(<i>X</i>,<i>Y</i>)</td>
<td valign="top">Return the first argument if the arguments are different, 
otherwise return NULL.</td>
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<td valign="top" align="right">quote(<i>X</i>)</td>
<td valign="top">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 current 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>

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<td valign="top" align="right">random(*)</td>
<td valign="top">Return a pseudo-random integer
between -9223372036854775808 and +9223372036854775807.</td>
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<td valign="top" align="right">
<a name="replaceFunc"></a>
replace(<i>X</i>,<i>Y</i>,<i>Z</i>)</td>
<td valign="top">Return a string formed by substituting string <i>Z</i> for
every occurrance of string <i>Y</i> in string <i>X</i>.  The BINARY
collating sequence is used for comparisons.</td>
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<td valign="top" align="right">
<a name="randomblobFunc"></a>
randomblob(<i>N</i>)</td>
<td valign="top">Return a <i>N</i>-byte blob containing pseudo-random bytes.
<i>N</i> should be a postive integer.</td>
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<td valign="top" align="right">round(<i>X</i>)<br>round(<i>X</i>,<i>Y</i>)</td>
<td valign="top">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>
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<td valign="top" align="right">
<a name="rtrimFunc"></a>
rtrim(<i>X</i>)<br>rtrim(<i>X</i>,<i>Y</i>)</td>
<td valign="top">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>
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<td valign="top" align="right">soundex(<i>X</i>)</td>
<td valign="top">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>
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<td valign="top" align="right">sqlite_version(*)</td>
<td valign="top">Return the version string for the SQLite library
that is running.  Example:  "2.8.0"</td>
</tr>

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<td valign="top" align="right">
  substr(<i>X</i>,<i>Y</i>,<i>Z</i>)<br>
  substr(<i>X</i>,<i>Y</i>)</td>
<td valign="top">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>
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<td valign="top" align="right">
<a name="trimFunc"></a>
trim(<i>X</i>)<br>trim(<i>X</i>,<i>Y</i>)</td>
<td valign="top">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>
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<td valign="top" align="right">typeof(<i>X</i>)</td>
<td valign="top">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>

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<td valign="top" align="right">upper(<i>X</i>)</td>
<td valign="top">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 
UTF-8 strings.</td>
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<td valign="top" align="right">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>

<b>Date And Time Functions</b>

<p>Date and time functions are documented in the 
<a href="http://www.sqlite.org/cvstrac/wiki?p=DateAndTimeFunctions">
SQLite Wiki</a>.</p>

<a name="aggregatefunctions"></a>
<b>Aggregate Functions</b>

<p>
The aggregate functions shown below are available by default.  Additional
aggregate functions written in C may be added using the 

<a href="c3ref/create_function.html">sqlite3_create_function()</a></a>
API.</p>

<p>
In any aggregate function that takes a single argument, that argument
can be preceeded by the keyword DISTINCT.  In such cases, duplicate
elements are filtered before being passed into the aggregate function.
For example, the function "count(distinct X)" will return the number
of distinct values of column X instead of the total number of non-null
values in column X.
</p>

<table border=0 cellpadding=10 class="pdf_functions">
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<td valign="top" align="right" width=120>avg(<i>X</i>)</td>
<td valign="top">Return the average value of all non-NULL <i>X</i> within a
group.  String and BLOB values that do not look like numbers are
interpreted as 0.
The result of avg() is always a floating point value even if all
inputs are integers. </p></td>
</tr>

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<td valign="top" align="right">count(<i>X</i>)<br>count(*)</td>
<td valign="top">The first form return a count of the number of times
that <i>X</i> is not NULL in a group.  The second form (with no argument)
returns the total number of rows in the group.</td>
</tr>

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<td valign="top" align="right">group_concat(<i>X</i>)<br>
group_concat(<i>X</i>,<i>Y</i>)</td>
<td valign="top">The result is a string which is the concatenation of
all non-NULL values of <i>X</i>.  If parameter <i>Y</i> is the separator
between instances of <i>X</i>.  A comma (",") is used as the separator
if <i>Y</i> is omitted.</td>
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<td valign="top" align="right">max(<i>X</i>)</td>
<td valign="top">Return the maximum value of all values in the group.
The usual sort order is used to determine the maximum.</td>
</tr>

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<td valign="top" align="right">min(<i>X</i>)</td>
<td valign="top">Return the minimum non-NULL value of all values in the group.
The usual sort order is used to determine the minimum.  NULL is only returned
if all values in the group are NULL.</td>
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<td valign="top" align="right">sum(<i>X</i>)<br>total(<i>X</i>)</td>
<td valign="top">Return the numeric sum of all non-NULL values in the group.
   If there are no non-NULL input rows then sum() returns
   NULL but total() returns 0.0.
   NULL is not normally a helpful result for the sum of no rows
   but the SQL standard requires it and most other
   SQL database engines implement sum() that way so SQLite does it in the
   same way in order to be compatible.   The non-standard total() function
   is provided as a convenient way to work around this design problem
   in the SQL language.</p>

   <p>The result of total() is always a floating point value.
   The result of sum() is an integer value if all non-NULL inputs are integers.
   If any input to sum() is neither an integer or a NULL
   then sum() returns a floating point value
   which might be an approximation to the true sum.</p>

   <p>Sum() will throw an "integer overflow" exception if all inputs
   are integers or NULL
   and an integer overflow occurs at any point during the computation.
   Total() never throws an exception.</p>
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</table>


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This page last modified 2007/12/20 21:09:25 UTC
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