On May 26, 2009, at 6:37 PM, Brandon Metcalf wrote:
j> option 2: case when '$length' = '' ...
j> you can use case like this:
j> UPDATE foo
j> SET
j> pattern = '$pattern',
j> shape = '$shape',
j> length = case when '$length'='' then length else
'$length' end,
j> comment = '$comment'
j> WHERE foo_id = $foo_id
j> here you can substitute any value you choose for the empty string,
j> 0 or NULL may (or may not) be more apropriate.
The issue here is that these reduce back to my original problem. For
example, if I use a CASE statement and I fall through to the ELSE,
then the SQL is attempting to insert a "''" in a NUMERIC field which
is not valid. That is, it's trying to do
No it doesn't, read that statement again ;)
If $length = 'foo' it reads (leaving out the extra fields):
UPDATE foo
SET length = CASE WHEN 'foo'='' THEN length ELSE 'foo' END
WHERE foo_id = $foo_id;
Which evaluates to:
UPDATE foo SET length = 'foo' WHERE foo_id = $foo_id;
Whereas if $length = '' it reads:
UPDATE foo
SET length = CASE WHEN ''='' THEN length ELSE '' END
WHERE foo_id = $foo_id
Which evaluates to:
UPDATE foo SET length = length WHERE foo_id = $foo_id
Alban Hertroys
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