<primary>extract</primary>

</indexterm>

<function>extract</function> ( <parameter>field</parameter> <literal>from</literal> <type>timestamp</type> )

<returnvalue>double precision</returnvalue>

<returnvalue>numeric</returnvalue>

</para>

<para>

Get timestamp subfield; see <xref linkend="functions-datetime-extract"/>

<row>

<entry role="func_table_entry"><para role="func_signature">

<function>extract</function> ( <parameter>field</parameter> <literal>from</literal> <type>interval</type> )

<returnvalue>double precision</returnvalue>

<returnvalue>numeric</returnvalue>

</para>

<para>

Get interval subfield; see <xref linkend="functions-datetime-extract"/>

well.) <replaceable>field</replaceable> is an identifier or

string that selects what field to extract from the source value.

The <function>extract</function> function returns values of type

<type>double precision</type>.

<type>numeric</type>.

The following are valid field names:

<!-- alphabetical -->

be a string value, not a name. The valid field names for

<function>date_part</function> are the same as for

<function>extract</function>.

For historical reasons, the <function>date_part</function> function

returns values of type <type>double precision</type>. This can result in

a loss of precision in certain uses. Using <function>extract</function>

is recommended instead.

</para>

<screen>

{$$ = makeTypeCast($3,$5,@1); }

{

$$ = (Node *) makeFuncCall(SystemFuncName("date_part"),

$$ = (Node *) makeFuncCall(SystemFuncName("extract"),

$3,

COERCE_SQL_SYNTAX,

@1);