有條件地刪除並插入postgres

Question

我有兩個表Table_A和Table_B 。 如何編寫執行以下邏輯的條件SQL

If table A records match table B records on id
then
    delete records from table A and Insert records into Table B

我該如何使用SQL最有可能with

delete from Table_A where Exists (select a.id from TABLE_A
join TABLE_B as b on a.id = b.id)

插入為： Insert into Table_A (id) select id from TABLE_B

Answer 1

使用CTE捕獲已刪除記錄的ID，然后將其與b記錄重新連接：

WITH del AS (
        DELETE FROM a
        WHERE EXISTS ( SELECT *
                FROM b
                WHERE b.id = a.id
                )
        returning *
        )
INSERT INTO a (id, x, y, z)
SELECT id, x, y, z
FROM b
WHERE EXISTS (
        SELECT *
        FROM del
        WHERE del.id = b.id
        );

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順便說一句：您應該有充分的理由 （例如想要激活觸發器），希望刪除+插入而不是更新。