Question

我正面临SQL Server的SQL查询问题。

我有一个像这样的查询。

SELECT QUOTENAME(A, '"'),
 QUOTENAME(B, '"'),
 QUOTENAME(C, '"')

FROM TABLENAME

现在，我必须用CASE语句替换它。

现在这个查询有效 -

SELECT A,
CASE
WHEN B='Thank you' then 'TY'
WHEN B='No Problem' then 'NP'
WHEN B='As soon as possible' then 'ASAP'
END AS B,
C
FROM TABLENAME

现在我正在使用QUOTENAME，因为我想用双引号括起字段。任何可能的场景我如何混合QUOTENAME和CASE语句。无论我尝试过什么都会引发语法错误。

Answer 1

应该像这样工作

SELECT A,
       CASE
         WHEN B='Thank you' then QUOTENAME('TY', '"')
         WHEN B='No Problem' then QUOTENAME('NP', '"')
         WHEN B='As soon as possible' then QUOTENAME('ASAP', '"')
       END AS B,
       C
FROM TABLENAME

或更短

SELECT A,
       QUOTENAME( CASE
                    WHEN B='Thank you' then 'TY'
                    WHEN B='No Problem' then 'NP'
                    WHEN B='As soon as possible' then 'ASAP'
                  END, '"') AS B,
       C
FROM TABLENAME

Answer 2

与GuidoG解决方案相比，这可能会稍微缩短一点：

$pre_check = "select location from users where username='$username";
$result_pre_check = mysqli_query($conn, $pre_check);
$pre_remove = "delete from $result_pre_check where username='$username'";
mysqli_query($conn, $pre_remove);

如果您总是将单个列进行相等性比较，则只需编写SELECT A , QUOTENAME(CASE B WHEN 'Thank you' THEN 'TY' WHEN 'No Problem' THEN 'NP' WHEN 'As soon as possible' THEN 'ASAP' END, '"') AS B , C FROM TABLENAME;然后进行比较：CASE COLUMN_NAME等。

一起使用CASE语句和QUOTENAME

2 个答案: