Re: Indexes on XML tags?

[Alexander Barkov]

Yes, the returned value will be extracted as text,
but as MySQL is not strict about data types, the above should work.

However, in some cases it's really usefull to return a value
as a number, instead of text. You can use "number()" XPath type-cast
to return a value as a number.


These two queries demonstrate the difference:


mysql> select ExtractValue('<num>01</num>','/num');
+--------------------------------------+
| ExtractValue('<num>01</num>','/num') |
+--------------------------------------+
| 01 |
+--------------------------------------+
1 row in set (0.00 sec)

mysql> select ExtractValue('<num>01</num>','number(/num)');
+----------------------------------------------+
| ExtractValue('<num>01</num>','number(/num)') |
+----------------------------------------------+
| 1 |
+----------------------------------------------+
1 row in set (0.01 sec)