匹配条件时更改列值

Question

NULL仅当其他条件匹配时，我才需要替换列中的值。

Columns: Parent, Child, flag01, lag02

父列有很多NULL价值，但是我想更换null，只有当价值flag01和flag02为“OK”。

如果flag01和flag02都是 " Ok" 并且 Parent 为 NULL，则替换为 'CT_00000'。否则，保留原始值（当 NOT NULL 时）。

Answer 1

所以我虽然你想要一个选择语句。

select case when (parent is null and flag01 = 'OK' and flag02 = 'OK') 
       then 'CT_00000'
       else parent end as columnSomeName,
       Child, flag01, lag02
 from yourTable

Answer 2

UPDATE Table_Name
SET   Column_Name = 'CT_00000'
WHERE flag01 = 'OK'
AND   flag02 = 'OK'
AND   Parent IS NULL

只是为了选择数据

SELECT CASE WHEN (flag01 = 'OK' AND flag02 = 'OK' AND Parent IS NULL)
            THEN 'CT_00000'
            ELSE Column_Name END AS Column_Name
FROM Table_Name