Question

我有一个表（TABLE1），它有4列：

UID | PID | VALUE1 | VALUE2

我有另一个SQL语句（STMT）从一些其他表返回3列：

UID | PID | VALUE1

现在这里是我想要更新TABLE1的条件：

首先，将STMT中的UID和PID对与TABLE1中的那些对比，

对于不在TABLE1中的所有新UID和PID对，将新行从STMT插入到TABLE1中，设置TABLE1.VALUE2 = 0（我已经完成了这一行）
对于STMT和TABLE1中的现有UID和PID对，执行：

一个。如果TABLE1.VALUE2＆gt; 0，更新TABLE1.VALUE1 = STMT.VALUE1

湾如果TABLE1.VALUE2 = 0并且如果TABLE1.VALUE1！= STMT.VALUE1，则更新TABLE1.VALUE1 = STMT.VALUE1，否则不执行任何操作。

我无法提出条件2的解决方案。感谢所有帮助！

Answer 1

UPDATE (
    SELECT table1.UID
           ,table1.PID
           ,table1.value1 AS table1_value1
           ,table1.value2 AS table1_value2
           ,stmt.value1 AS stmt_value1
    FROM table1
    INNER JOIN (SELECT ? AS UID
                       ,? AS PID
                       ,? AS value1
                FROM whatever) stmt
        ON stmt.UID = table1.UID
        AND stmt.PID = table1.PID
) x
SET x.table1_VALUE1 = CASE WHEN (x.table1_VALUE2 > 0) OR
                              (x.table1_VALUE2 = 0 AND x.table1_VALUE1 <> x.stmt_VALUE1)
                              THEN x.stmt_VALUE1
                         ELSE x.table1_VALUE1 
                    END

Oracle SQL：根据与SQL语句的比较有条件地更新表

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