diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/func.sgml | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 7119f0b2ca5..f0658565350 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -2669,15 +2669,21 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue> <row> <entry role="func_table_entry"><para role="func_signature"> + <function>substring</function> ( <parameter>string</parameter> <type>text</type> <literal>SIMILAR</literal> <parameter>pattern</parameter> <type>text</type> <literal>ESCAPE</literal> <parameter>escape</parameter> <type>text</type> ) + <returnvalue>text</returnvalue> + </para> + <para role="func_signature"> <function>substring</function> ( <parameter>string</parameter> <type>text</type> <literal>FROM</literal> <parameter>pattern</parameter> <type>text</type> <literal>FOR</literal> <parameter>escape</parameter> <type>text</type> ) <returnvalue>text</returnvalue> </para> <para> Extracts substring matching <acronym>SQL</acronym> regular expression; - see <xref linkend="functions-similarto-regexp"/>. + see <xref linkend="functions-similarto-regexp"/>. The first form has + been specified since SQL:2003; the second form was only in SQL:1999 + and should be considered obsolete. </para> <para> - <literal>substring('Thomas' from '%#"o_a#"_' for '#')</literal> + <literal>substring('Thomas' similar '%#"o_a#"_' escape '#')</literal> <returnvalue>oma</returnvalue> </para></entry> </row> @@ -5160,7 +5166,11 @@ cast(-44 as bit(12)) <lineannotation>111111010100</lineannotation> The <function>substring</function> function with three parameters provides extraction of a substring that matches an SQL regular expression pattern. The function can be written according - to SQL99 syntax: + to standard SQL syntax: +<synopsis> +substring(<replaceable>string</replaceable> similar <replaceable>pattern</replaceable> escape <replaceable>escape-character</replaceable>) +</synopsis> + or using the now obsolete SQL:1999 syntax: <synopsis> substring(<replaceable>string</replaceable> from <replaceable>pattern</replaceable> for <replaceable>escape-character</replaceable>) </synopsis> @@ -5201,8 +5211,8 @@ substring(<replaceable>string</replaceable>, <replaceable>pattern</replaceable>, <para> Some examples, with <literal>#"</literal> delimiting the return string: <programlisting> -substring('foobar' from '%#"o_b#"%' for '#') <lineannotation>oob</lineannotation> -substring('foobar' from '#"o_b#"%' for '#') <lineannotation>NULL</lineannotation> +substring('foobar' similar '%#"o_b#"%' escape '#') <lineannotation>oob</lineannotation> +substring('foobar' similar '#"o_b#"%' escape '#') <lineannotation>NULL</lineannotation> </programlisting> </para> </sect2> |