[英]Replace 2 CTEs to one
我在 postgresql 上有以下代码:
WITH CTE1 AS
(
SELECT
value_1
,position
,value_3
,value_4
,value_5
From tabl_1
WHERE position = 1
)
WITH CTE2 AS
(
SELECT
value_1
,position
,value_3
,value_4
,value_5
From tabl_1
WHERE position = 2
)
INSERT INTO tbl_2
SELECT
CTE1.value_2 = IP_1
CTE2.value_2 = IP_2
FROM table_3 er
LEFT JOIN CTE1 ON CTE1.value_1 = er.value_1 AND CTE1.value_3 = er.value_3
LEFT JOIN CTE2 ON CTE2.value_1 = er.value_1 AND CTE2.value_3 = er.value_3
我在单独的 CTE 中计算 IP_1、IP-2 的值,但我不知道如何将 2 个 CTE 替换为一个? 或者其他方式。
复制你的代码,它似乎有很多错误:
这可以重构以删除所有 CTE:
INSERT INTO
tbl_2
SELECT
t1.value_2 = IP_1
t2.value_2 = IP_2
FROM
table_3 er
LEFT JOIN tabl_1 t1 ON t1.value_1 = er.value_1 AND t1.value_3 = er.value_3 AND t1.position = 1
LEFT JOIN tabl_1 t2 ON t2.value_1 = er.value_1 AND t2.value_3 = er.value_3 AND t2.position = 2
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