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Question

我的桌子如下

我想要输出如下

我尝试做以下事情

SELECT * FROM TABLE_NAME WHERE COLUMN2 = 'PQR' AND COLUMN3 IS NOT NULL

但是它也会从第一张表中删除3rd and 4th row。而在查询的输出中，我只需要删除具有Column2 as PQR and Column3 as NOT NULL

的行

我也尝试使用case语句，但是我无法真正了解如何实现它。

编辑1：-

我还想现在再尝试一件事。

SELECT * FROM TABLE_NAME WHERE COLUMN2 IN ('PQR', 'XYZ', 'RST') AND COLUMN3 IS NOT NULL

但是问题出在实际的表COLUMN2中，有150多个不同的值，我无法在IN子句中继续提及。

Answer 1

您想要的是（如果我理解正确的话）

NOT (COLUMN2 = 'PQR' AND COLUMN3 IS NOT NULL) 

等效于

COLUMN2!='PQR' OR COLUMN3 IS NULL

Answer 2

1. 不是（COLUMN2 ='PQR'并且COLUMN3不为空）

示例：

SQL> ;
  1  with -- test data:
  2   t(column1,column2,column3) as (
  3     select 'ABC','PQR',cast(null as int) from dual union all
  4     select 'DEF','PQR',123 from dual union all
  5     select 'GHI','XYZ',cast(null as int) from dual union all
  6     select 'JKL','RST',cast(null as int) from dual
  7  ) -- test query:
  8  select *
  9  from t
 10* where not(COLUMN2 = 'PQR' AND COLUMN3 IS NOT NULL)
SQL> /

COL COL    COLUMN3
--- --- ----------
ABC PQR NULL
GHI XYZ NULL
JKL RST NULL

或lnnvl（COLUMN2 ='PQR'）或COLUMN3为NULL

示例：

with -- test data:
 t(column1,column2,column3) as (
   select 'ABC','PQR',cast(null as int) from dual union all
   select 'DEF','PQR',123 from dual union all
   select 'GHI','XYZ',cast(null as int) from dual union all
   select 'JKL','RST',cast(null as int) from dual 
) -- test query:
select * 
from t
where lnnvl(COLUMN2 = 'PQR') or COLUMN3 IS NULL;

COL COL    COLUMN3
--- --- ----------
ABC PQR NULL
GHI XYZ NULL
JKL RST NULL