Question

我正在处理我输入的一个很大的查询，但是在这里我将其缩短。我想做的是选择一堆列，然后运行when并使用where not in子句来过滤结果，以便仅查看用户的授权。如果我从where子句中删除PERM NOT IN，它将返回授权和未授权用户的身份，而我不希望看到该情况。我不是100％不确定是否有可能，是否可以通过其他方式或更简单的方式来完成该工作，这是很好的。

这是我的查询：

SELECT 
    usname AS Name, ususer AS Username, usseclevel AS Default_Level, 
    usglsecl AS GL_SecurityLevel, aoopid, aoseclevel
    CASE 
       WHEN aoauopid >= 00500 AND aoAuOpID < 10000 
          THEN
             CASE 
                WHEN usglsecl >= aoseclevel 
                   THEN 'Authorized' 
                   ELSE 'Unauthorized' 
             END
    END AS PERM
FROM
    library.file 
JOIN
    library.file ON usseclevel >= aoseclevel
WHERE 
    ususer NOT IN ('*ALL', 'daffron') 
    AND PERM NOT IN ('Unauthorized, 'null')
ORDER BY 
    ususer

如果您希望我发布整个查询，则可以，但是我认为它不需要整个查询才能获得所需的输出。

Answer 1

由于我不确定您使用的是哪种SQL变体，因此我将不知所措。您通常不能在WHERE子句中使用列别名。在我头顶上方，我看到了三个选项：

选项1-使用“表表达式”从别名中产生一个真实的列名：

select * from (
  Select usname as Name, ususer as Username, usseclevel as Default_Level, 
  usglsecl as GL_SecurityLevel, aoopid, aoseclevel
  Case When aoauopid >=00500 and aoAuOpID <10000 then case when 
  usglsecl>=aoseclevel then 'Authorized' else 'Unauthorized' end END AS PERM
  from library.file join library.file on usseclevel>=aoseclevel
  WHERE ususer NOT IN('*ALL','daffron') 
) x
WHERE PERM NOT IN('Unauthorized,'null')
ORDER BY ususer

选项2-使用CTE（公用表表达式）：

with x as (
  Select usname as Name, ususer as Username, usseclevel as Default_Level, 
  usglsecl as GL_SecurityLevel, aoopid, aoseclevel
  Case When aoauopid >=00500 and aoAuOpID <10000 then case when 
  usglsecl>=aoseclevel then 'Authorized' else 'Unauthorized' end END AS PERM
  from library.file join library.file on usseclevel>=aoseclevel
  WHERE ususer NOT IN('*ALL','daffron') 
)
select * from x 
WHERE PERM NOT IN('Unauthorized,'null')
ORDER BY ususer

选项3-在WHERE子句中（而不是PERM）再次重复整个CASE：

Select usname as Name, ususer as Username, usseclevel as Default_Level, 
usglsecl as GL_SecurityLevel, aoopid, aoseclevel
Case When aoauopid >=00500 and aoAuOpID <10000 then case when 
usglsecl>=aoseclevel then 'Authorized' else 'Unauthorized' end END AS PERM
from library.file join library.file on usseclevel>=aoseclevel
WHERE ususer NOT IN('*ALL','daffron') 
and Case When aoauopid >=00500 and aoAuOpID <10000 then case when 
usglsecl>=aoseclevel then 'Authorized' else 'Unauthorized' end END
    NOT IN('Unauthorized,'null')
ORDER BY ususer

SQL：在where子句中调用时的情况

1 个答案: