Hello.
On Mon, Apr 08, 2002 at 11:24:56AM -0400, [EMAIL PROTECTED] wrote:
[...]
> still...I wonder why I got a 'Query OK, 1 row affected' message....
[...]
> > insert into table (key, field) values (1, 'test'||CHAR(59)||' string');
> >
> > it seems to work initially...(Query OK, 1 row affected (0.00 sec))
> > but when I try to select the value of the field I get just the
> > value '0' (string of zero).
[...]
That's because it is a valid expression. In the context of ||, 'test'
will be converted to a number. Same for CHAR(59) which returns a
string:
mysql> SELECT 'test' + 0, 'test' || 0, CHAR(59) || 0, VERSION();
+------------+-------------+---------------+-------------------+
| 'test' + 0 | 'test' || 0 | CHAR(59) || 0 | VERSION() |
+------------+-------------+---------------+-------------------+
| 0 | 0 | 0 | 3.23.42-debug-log |
+------------+-------------+---------------+-------------------+
1 row in set (0.00 sec)
ORing the expressions with || results in a boolean value which is
represented by 1 (true) or 0 (false) respectively. So your insert
INSERT INTO table1 (key, field) VALUES (1, 'test'||CHAR(59)||' string')
statement boils down to
INSERT INTO table1 (key, field) VALUES (1, 0)
which is perfectly valid.
Well, with some other strings, you could get even a 1 as result :-)
mysql> SELECT '21test' || 0, CHAR(53) || 0;
+---------------+---------------+
| '12test' || 0 | CHAR(53) || 0 |
+---------------+---------------+
| 1 | 1 |
+---------------+---------------+
1 row in set (0.00 sec)
Bye,
Benjamin.
--
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