嵌套MySQL语句问题

Question

我有以下生成的列修改，它给我抛出了一个错误。我最近使用类似的嵌套案例修改了它，但后来意识到我没有保存查询，并且我需要更新一项检查，因此需要更新它。

 ALTER TABLE
    `t1` MODIFY COLUMN `criteria` GENERATED ALWAYS AS(
        CASE WHEN `status` = 'Active' THEN
            CASE WHEN `exempt` = 'FALSE' AND `age` < 35 THEN
                CASE WHEN `experience` = "Pro" AND `rule` = 'Descendent' THEN 6 
                WHEN `experience` = "Pro" AND `rule` != 'Descendent' THEN 5 
                WHEN `experience` = 'Division I' AND `rule` = 'Descendent' THEN 5 
                WHEN `experience` = 'Division I' AND `rule` != 'Descendent' THEN 4 
                WHEN `experience` = 'Division II' AND `rule` = 'Descendent' THEN 4 
                WHEN `experience` = 'Division II' AND `rule` != 'Descendent' THEN 3 
                WHEN `experience` = 'Division III' AND `rule` = 'Descendent' THEN 3 
                WHEN `experience` = 'Division III' AND `rule` != 'Descendent' THEN 2 
                WHEN `experience` = 'NAIA' AND `rule` = 'Descendent' THEN 3 
                WHEN `experience` = 'NAIA' AND `rule` != 'Descendent' THEN 2 
                WHEN `experience` = 'Junior College' AND `rule` = 'Descendent' THEN 2 
                WHEN `experience` = 'Junior College' AND `rule` != 'Descendent' THEN 1 
                WHEN `experience` = 'High School' AND `rule` = 'Descendent' THEN 1 
                ELSE 0
                END
         ELSE 0
         END
 ELSE 0
 END
) STORED

谁能告诉我我在这里缺少什么？我一生都无法弄清楚我错过了什么。提前致谢！ 这是来自 MySql 的错误：

MySQL said: Documentation

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'GENERATED ALWAYS AS(
        CASE WHEN `status` = 'Active' THEN
            CA' at line 2

Answer 1

即使对于生成的列，您也必须指定数据类型作为列定义的一部分。

ALTER TABLE
`t1` MODIFY COLUMN `criteria` _______________________ GENERATED ALWAYS AS ...
                              ^ data type goes here ^