Question

如何在mysql的where子句中使用别名？

SELECT 
    *,
    CASE roles.rol_active
        WHEN '1' THEN 'yes'
        WHEN '0' THEN 'no'
    END AS roles_active
FROM
    roles
WHERE
    rol_is_deleted = 
 AND (rol_name LIKE '%ac%' 
  OR rol_display_name LIKE '%ac%'
  OR rol_description LIKE '%ac%'
  OR rol_active LIKE '%ac%'
  OR rol_updated_by LIKE '%ac%'
  OR rol_updated_at LIKE '%ac%')
ORDER BY rol_name asc
LIMIT 10 OFFSET 0;

Answer 1

实际上你不能，因为select子句在where子句之后被评估（此时没有别名）。但是，您可以使用having子句或使用临时表。

Answer 2

将当前查询的一部分包含在派生表中：

select * from
(
SELECT 
    *,
    CASE roles.rol_active
        WHEN '1' THEN 'yes'
        WHEN '0' THEN 'no'
    END AS roles_active
FROM
    roles
) as dt
WHERE
    rol_is_deleted = 
 AND (rol_name LIKE '%ac%' 
  OR rol_display_name LIKE '%ac%'
  OR rol_description LIKE '%ac%'
  OR rol_active LIKE '%ac%'
  OR rol_updated_by LIKE '%ac%'
  OR rol_updated_at LIKE '%ac%')
ORDER BY rol_name asc
LIMIT 10 OFFSET 0;

您甚至可以有两个单独的WHERE条款。一个用于子查询中的列条件，另一个用于外部查询中的列别名条件。即类似的东西：

...
WHERE column-conditions
) as dt
WHERE column-alias-conditions
...

如何在MySQL的where子句中使用别名？

2 个答案: