Question

在我的SQL查询中，我需要对别名进行一些算术运算。

SELECT 
    MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME1, 
    MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME2,  
    MYALIASNAME1 - MYALIASNAME2 AS MYALIASHNAME3
FROM 
    MYTABLE

但是，这不起作用，因为它不会将MYALIASNAME1和MYALIASNAME2视为列。任何想法我怎样才能做到这一点？

我正在使用H2，特别是h2-1.3.173.jar。我在服务器模式下使用它。

感谢。

Answer 1

试试这个。

SELECT X.MYALIASNAME1 - X.MYALIASNAME2 AS MYALIASNAME3 FROM
(
    SELECT 
        MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME1, 
        MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME2

    FROM 
        MYTABLE
)X

Answer 2

use cte expressions

用cte作为（

    select MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME1, 
        MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME2

    from table

)

select MYALIASNAME1 - MYALIASNAME2 AS MYALIASHNAME3 from cte

Answer 3

不要使用别名

SELECT 
   MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME1, 
   MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME2,  
   MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN  - MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASHNAME3
FROM 
    MYTABLE

或使用中间步骤

SELECT MYALIASNAME1, MYALIASNAME2,  MYALIASNAME1 - MYALIASNAME2 AS MYALIASHNAME3
FROM  (

   SELECT 
       MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME1, 
       MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME2
   FROM 
       MYTABLE
 ) TableAlias

Answer 4

它会起作用......

"SELECT 
    MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME1, 
    MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN AS MYALIASNAME2,  
    (MY_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN) - (MY_SECOND_COMPLEX_EXPRESSION_USING_SUM_AND_CASEWHEN) AS MYALIASHNAME3
FROM 
    MYTABLE"

在SQL中对别名进行算术运算

4 个答案: