POSIX Regular Expressions on xml type fields - Mailing list pgsql-general

From Denis Papathanasiou
Subject POSIX Regular Expressions on xml type fields
Date
Msg-id CAEpnaGzL29NXbWvUZt6A=bOx+8wH5Z+nmr0qL98gZKCp_HRgAA@mail.gmail.com
Whole thread Raw
List pgsql-general
I have a table with an xml type column, and while I can make regex
queries like this successfully:

=> select id from form_d where 'kumar' ~* any(
CAST(xpath('//PersonsList/PersonName/LastName/text()', data) as
TEXT[]) );
                  id
--------------------------------------
 97e1541b-27f4-4d95-beb5-2f67830ebc48
(1 row)

and

=> select id from form_d where '(kumar|gonzales)' ~* any(
CAST(xpath('//PersonsList/PersonName/LastName/text()', data) as
TEXT[]) );
                  id
--------------------------------------
 aea32e7e-f422-405c-953b-86fe3c8c1e30
 97e1541b-27f4-4d95-beb5-2f67830ebc48
(2 rows)

I.e., they are successful in that the last names in the xml data are
"Kumar" and "Gonzales", so the ~* operator handled the case comparison
correctly, and the (|) grouping also found the two rows where the
corresponding xml had "Kumar" and "Gonzales" in the PersonList
attribute.

But if I change the expression to ask for all last names beginning
with "Kuma" or "Gonza", like this, the query returns no matches:

=> select id from form_d where '^kuma' ~* any(
CAST(xpath('//PersonsList/PersonName/LastName/text()', data) as
TEXT[]) );
 id
----
(0 rows)

=> select id from form_d where '^gonza' ~* any(
CAST(xpath('//PersonsList/PersonName/LastName/text()', data) as
TEXT[]) );
 id
----
(0 rows)

=> select id from form_d where '^(kuma|gonza)' ~* any(
CAST(xpath('//PersonsList/PersonName/LastName/text()', data) as
TEXT[]) );
 id
----
(0 rows)

Why is that?


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