"C.R.Vegelin" <[EMAIL PROTECTED]> wrote:
>
> Hi everybody,
> I looked for a function to test whether a string is numeric (having
> characters 0..9 only). I found in the 5.0 manual Cast() and Convert(), but
> I don't think these do what I need. Any suggestion what function to use ?
> Thanks in advance, Cor
Gleb Paharenko wrote:
Hello.
Possible solution is to use REGEXP:
mysql> select '911' regexp '^[1-9]*$';
+-------------------------+
| '911' regexp '^[1-9]*$' |
+-------------------------+
| 1 |
+-------------------------+
mysql> select '91a1' regexp '^[1-9]*$';
+--------------------------+
| '91a1' regexp '^[1-9]*$' |
+--------------------------+
| 0 |
+--------------------------+
This is close, but not quite what you want, I think. The problem is that this
will also match empty strings:
mysql> SELECT '' REGEXP '^[1-9]*$';
+----------------------+
| '' REGEXP '^[1-9]*$' |
+----------------------+
| 1 |
+----------------------+
1 row in set (0.00 sec)
That's easily fixed, though. Just change the * to a +.
mysql> SELECT '' REGEXP '^[1-9]+$';
+----------------------+
| '' REGEXP '^[1-9]+$' |
+----------------------+
| 0 |
+----------------------+
1 row in set (0.00 sec)
Michael
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