多个SQL语句

Question

$sql = "UPDATE user SET `niveua`='beginner' WHERE `km`< 50";  
$result = $con->query($sql);

$sql = "UPDATE user SET `niveua`='trained' WHERE `km`> 50 or `km` < 99";  
$result = $con->query($sql);

$sql = "UPDATE user SET `niveua`='expert' WHERE `km`> 100";  
$result = $con->query($sql);

我无法使用这3条SQL。 这只是正在更新的第三个。 那么我如何让这3个都正常工作呢？

Answer 1

缺少AND ，您也可以像下面这样简化查询，这样可以更快

UPDATE user 
SET niveua = 
CASE 
     WHEN (`km` < 50 )
         THEN 'beginner'
     WHEN (`km`> 50 AND `km` < 99 )
         THEN 'trained' 
     WHEN ( `km` > 100 )
         THEN 'expert' 
     ELSE niveua 
END;