Question

我有一个查询将值插入表中，并使用CASE来确定每行的值。我想知道在它结束时是否有可能从计算列中排除null或零？

   CASE
       WHEN Value = 0 THEN Value2
       WHEN Value2 < Value1 THEN Value3
       WHEN Value2 > Value1 THEN Value4
   END AS Final_Value

这会产生几十万行，其中几千行现在为零或为零。我可以在同一段代码中排除这些吗？

由于

Answer 1

使用where子句：

select 
   ...
 , case 
  when value = 0
   then value2
  when value2 < value1
   then value3
  when value2 > value1
   then value4
  end as final_value
from  ...
where case
       when value = 0 then value2
       when value2 < value1 then value3
       when value2 > value1 then value4
   end <> 0

Answer 2

在查询结束时可以避免0或null值，如

SELECT  
ACCGRPID, 
LOCID, 
USERID4, 
LOBNAME, 
REINSTYPE, 
INCEPTDATE, 
EXPIREDATE, 
Latitude, 
Longitude, 
CountryRMSCode, 
StreetAddress, 
CityName, 
ACCGRPNUM, 
ACCGRPNAME,    
CASE
   WHEN Value = 0 THEN Value2
   WHEN Value2 < Value1 THEN Value3
   WHEN Value2 > Value1 THEN Value4
END AS Final_Value
FROM  <table_name>
WHERE Final_Value <> 0

Answer 3

   ;WITH CTE AS (
       select
          ACCGRPID, 
          LOCID, 
          USERID4, 
          LOBNAME, 
          REINSTYPE, 
          INCEPTDATE, 
          EXPIREDATE, 
          Latitude, 
          Longitude, 
          CountryRMSCode, 
          StreetAddress, 
          CityName, 
          ACCGRPNUM, 
          ACCGRPNAME,    
          CASE
                 WHEN Value = 0 THEN Value2
                WHEN Value2 < Value1 THEN Value3
                 WHEN Value2 > Value1 THEN Value4
          END AS Final_Value
   )
   select * from CTE
   where  Final_Value <> 0 
          and Final_Value is not null

Answer 4

如果无法在where子句中进行过滤，那么在某些情况下我会使用一个简单的解决方案，并使用子选择。

示例：

select X.* from (
SELECT 
     ACCGRPID, 
     LOCID, 
     USERID4, 
     LOBNAME, 
     REINSTYPE, 
     INCEPTDATE, 
     EXPIREDATE, 
     Latitude, 
     Longitude, 
     CountryRMSCode, 
     StreetAddress, 
     CityName, 
     ACCGRPNUM, 
     ACCGRPNAME,
     CASE
        WHEN Value = 0 THEN Value2
        WHEN Value2 < Value1 THEN Value3
        WHEN Value2 > Value1 THEN Value4
     END AS Final_Value
    from <table_name>) X
where X.Final_Value != 0 and X.Final_Value is not null

Answer 5

检查案例，以便它不会导致0或NULL

例如：

CASE
WHEN Value = 0 THEN Value2
WHEN Value2 <= Value1 THEN Value3
WHEN Value2 > Value1 THEN Value4
ELSE Value2
END AS Final_Value

当然，这个假定Value2，Value3和Value4是非NULL而不是0。

SQL从案例列中排除零

5 个答案: