Hello all,
I'm trying to get a TEXT field updated with its own content and an extra
string by using concat. The query looks something like this:
update field_comment set field_comment = concat(field_comment, '\n
my_new_string');
I've noticed that in this case the update doesn't work when the content of
the field is empty. I tried setting up a testcase, and as long as the
textfield is NULL concat doesn't return anything. Is this 'as designed' or a
bug? Should it work as designed, would anyone know another easy way without
setting a byte first?
Below the testcase:
CREATE TABLE memo_test (id INT (1) UNSIGNED DEFAULT '0' NOT NULL, comments
TEXT, PRIMARY KEY(id)) TYPE = MyISAM;
INSERT INTO memo_test (id, comments) VALUES (1, NULL);
INSERT INTO memo_test (id, comments) VALUES (2, 'Hello');
select concat(comments, 'Does not work') from memo_test
+-----------------------------------+
| concat(comments, 'Does not work') |
+-----------------------------------+
| NULL |
| HelloDoes not work |
+-----------------------------------+
select concat('Something', comments, 'Does not work') from memo_test;
+------------------------------------------------+
| concat('Something', comments, 'Does not work') |
+------------------------------------------------+
| NULL |
| SomethingHelloDoes not work |
+------------------------------------------------+
Best regards,
Almar van Pel
www.makeweb.nl
