Question

请帮助我。

SELECT
   Username,
   CASE
      WHEN UserType = 'DUMMY' AND UserLoginId = Username THEN 'Awaiting_Approval'
      WHEN UserType = 'DUMMY' AND UserLoginId != Username THEN 'Checking_Approval'
      ELSE 'No_Status_Yet'
   END AS UserStatus
FROM MyTable
WHERE UserStatus LIKE '%king%'

我尝试通过数据库中的文本创建简单搜索，因此我可以在文本的中间进行搜索。由于那里没有状态列，我自己从2列详细信息的组合创建它。谁能帮我。感谢。

Answer 1

您不能在WHERE子句中直接使用别名，请尝试下面的

SELECT  *
FROM    (
    SELECT  Username,
           CASE
              WHEN UserType = 'DUMMY' AND UserLoginId = Username THEN 'Awaiting_Approval'
              WHEN UserType = 'DUMMY' AND UserLoginId != Username THEN 'Checking_Approval'
              ELSE 'No_Status_Yet'
           END AS UserStatus
    FROM MyTable
)   AS  D
WHERE UserStatus LIKE '%king%'

Answer 2

作为替代方案，您可以在WHERE子句中添加案例表达式。

喜欢

SELECT
   Username,
   'Checking_Approval' AS UserStatus
FROM MyTable
WHERE 1 = CASE WHEN UserType = 'DUMMY' AND UserLoginId != Username THEN 1
          --other conditions that should be returned here
            ELSE 0
          END

Answer 3

您可以使用HAVING关键字（仅适用于MySQL）：

SELECT
    Username,
    CASE
        WHEN UserType = 'DUMMY' AND UserLoginId = Username THEN 'Awaiting_Approval'
        WHEN UserType = 'DUMMY' AND UserLoginId != Username THEN 'Checking_Approval'
        ELSE 'No_Status_Yet'
        END AS UserStatus
FROM MyTable
HAVING UserStatus LIKE '%king%'

来自CASE语句的SQL搜索脚本

3 个答案: