3 replies to this topic

[Hostile]

I'm trying to take somebody else's code who used to work my job but is gone and add a sort order. Right now it's ascending by date. I need it to descend.

$Query='select * from '.$Category.' where isAvailable<>""';

Normally this would be done by adding this

SELECT * FROM table_name
ORDER BY Date DESC

I tried this but it didn't work.

$Query='select * from '.$Category.' ORDER BY Date DESC where isAvailable<>""';

I know it's something simple as I'm not the best coder around. Any help will do.

[Beowulf]

The WHERE clause has to precede the ORDER BY. In short, move the ORDER BY to the end of the statement.

[Bart]

As a general rule, clauses in the query must be given in the order they will be executed (SELECT is an exception), so:

- You need to filter the result before you can sort it -> WHERE comes before ORDER
- Grouping must be done after filtering -> WHERE comes before GROUP BY
- HAVING lets you add another filter after grouping has been done -> HAVING comes after GROUP BY
- Only after you've filtered, grouped and whatnot can you determine what the first X rows are -> LIMIT comes last
- etc...

[Jeeves]

Or WOGHL for short, which doesn't make it any easier to remember
Also, if you have access to phpMyAdmin, use it. Echo your query to check the variables are appearing right, then copy-paste to phpMyAdmin's query box and you can easily see any errors and try changes faster than through editing the PHP.