WHERE子句中的mysql计算结果

Question

I would like to select my results using calculations inside the query and use these results to compare inside the WHERE statement. But somehow that does not work. Guess you know why? Here is my code:

$statement = $pdo->prepare("SELECT * ,  `ft_lteam` -  `ht_lteam` AS  `ht2_lteam`,  
`ft_vteam` -  `ht_vteam` AS  `ht2_vteam` 
FROM  `sca` 
WHERE `ht2_lteam` > `ht2_vteam`");
$statement->execute(array('Max'));

Help would be great. Thanks for that!

Answer 1

You can use HAVING to filter on a computed column:

$statement = $pdo->prepare("SELECT * ,  `ft_lteam` -  `ht_lteam` AS  `ht2_lteam`,  
`ft_vteam` -  `ht_vteam` AS  `ht2_vteam` 
FROM  `sca` 
HAVING `ht2_lteam` > `ht2_vteam`");
$statement->execute(array('Max'));

Clear example here

SELECT col1,col2,col3,(col1*col2*col3) AS result, number FROM table
HAVING result > number
ORDER by result