PostgreSQL - 使用子查询更新多个列值

Question

我需要能够使用子查询的结果更新表上的多个列。一个简单的示例如下所示 -

UPDATE table1
SET (col1, col2) =
  ((SELECT MIN (ship_charge), MAX (ship_charge) FROM orders))
WHERE col4 = 1001; 

如何在 PostgreSQL 中执行此操作？

感谢您的任何提示！

更新：我很抱歉使示例对于我的实际用例来说过于简单。下面的查询更准确 -

UPDATE table1
SET    (TOTAL_MIN_RATE, TOTAL_MAX_RATE) = (SELECT AVG(o.MIN_RATE), AVG(o.MAX_RATE)
                           FROM   ORDR o INNER JOIN table2 ba ON (o.PAY_ACCT_ID = ba.ACCT_ID) 
                                         INNER JOIN table3 mb ON (ba.BANK_ID = mb.BANK_ID)
                               WHERE  ba.CNTRY_ID = table1.CNTRY_ID AND 
                                              o.STUS_CD IN ('01','02','03','04','05','06') AND
                                  ((o.FRO_CRNCY_ID = table1.TO_CRNCY_ID AND o.TO_CRNCY_ID = table1.FRO_CRNCY_ID) OR
                                   (o.TO_CRNCY_ID = table1.TO_CRNCY_ID AND o.FRO_CRNCY_ID = table1.FRO_CRNCY_ID))   
                               GROUP BY ba.CNTRY_ID)

Answer 1

这不是最有效的方法，但很简单：

UPDATE table1 SET
col1 = (SELECT MIN (ship_charge) FROM orders),
col2 = (SELECT MAX (ship_charge) FROM orders)
WHERE col4 = 1001; 

Answer 2

一种选择（但不是唯一的选择）是使用两个单独的子查询：

update table1
set col1 = (select min(ship_charge) from orders),
    col2 = (select max(ship_charge) from orders)
where col4 = 1001;

来自 PostgreSQL 9.0的更新精细手册：

根据标准，列列表语法应允许从单个行值表达式（例如子选择）分配列列表：

更新帐户 SET (contact_last_name, contact_first_name) =
（从销售人员中选择姓氏、名字
 WHERE salesmen.id = 账户.sales_id);

目前尚未实现 - 源必须是独立表达式的列表。

Answer 3

当您没有简单的子选择时，使用 UPDATE FROM 是一个很好的解决方案。在此UPDATE中，我想将photos表的event_profile_id设置为照片集的所有者（事件配置文件也是所有者）照片属于.

UPDATE photos
SET event_profile_id=photos_and_events.event_profile_id
FROM (
  SELECT
    ph.id photo_id,
    pr.id event_profile_id
  FROM photos ph, profiles pr, photo_sets ps
  WHERE ph.main_photo_set_id=ps.id AND ps.owner_profile_id=pr.id
) AS photos_and_events
WHERE photos.id=photos_and_events.photo_id;

Answer 4

正如官方文档所说：您可以使用标准更新PostgreSQL更新概要

UPDATE table
    SET { column = { expression | DEFAULT } |
          ( column [, ...] ) = ( { expression | DEFAULT } [, ...] ) } [, ...]
    [ FROM from_list ]
    [ WHERE condition ]

所以你可以使用这样的写法：

UPDATE table1
SET TOTAL_MIN_RATE = subQuery."minRate",
 TOTAL_MAX_RATE = subQuery.maxRate
FROM
    (
        SELECT
            AVG (o.MIN_RATE) AS minRate,
            AVG (o.MAX_RATE) AS maxRate
        FROM
            ORDR o
        INNER JOIN table2 ba ON (o.PAY_ACCT_ID = ba.ACCT_ID)
        INNER JOIN table3 mb ON (ba.BANK_ID = mb.BANK_ID)
        WHERE
            ba.CNTRY_ID = table1.CNTRY_ID
        AND o.STUS_CD IN (
            '01',
            '02',
            '03',
            '04',
            '05',
            '06'
        )
        AND (
            (
                o.FRO_CRNCY_ID = table1.TO_CRNCY_ID
                AND o.TO_CRNCY_ID = table1.FRO_CRNCY_ID
            )
            OR (
                o.TO_CRNCY_ID = table1.TO_CRNCY_ID
                AND o.FRO_CRNCY_ID = table1.FRO_CRNCY_ID
            )
        )
        GROUP BY
            ba.CNTRY_ID
    ) subQuery;

或者更简单的方法：

UPDATE table1
SET (
    TOTAL_MIN_RATE,
    TOTAL_MAX_RATE
) = (
    SELECT
        AVG (o.MIN_RATE) AS minRate,
        AVG (o.MAX_RATE) AS maxRate
    FROM
        ORDR o
    INNER JOIN table2 ba ON (o.PAY_ACCT_ID = ba.ACCT_ID)
    INNER JOIN table3 mb ON (ba.BANK_ID = mb.BANK_ID)
    WHERE
        ba.CNTRY_ID = table1.CNTRY_ID
    AND o.STUS_CD IN (
        '01',
        '02',
        '03',
        '04',
        '05',
        '06'
    )
    AND (
        (
            o.FRO_CRNCY_ID = table1.TO_CRNCY_ID
            AND o.TO_CRNCY_ID = table1.FRO_CRNCY_ID
        )
        OR (
            o.TO_CRNCY_ID = table1.TO_CRNCY_ID
            AND o.FRO_CRNCY_ID = table1.FRO_CRNCY_ID
        )
    )
    GROUP BY
        ba.CNTRY_ID
);

Answer 5

我需要在一个表上进行多次插入，从两个表中获取数据，而它们之间没有公共列，并忽略已经存在的记录。

以下 sql 在 Postgresql 11 上进行了测试，尽管它在 v9+ 上应该可以正常工作：

WITH permission_info AS (
    SELECT id
    FROM permission
    WHERE permission."key" LIKE 'prefix_for_admin_%'
), role_info AS (
    SELECT id 
    FROM role
    WHERE role."name" = 'Admin'
)
INSERT INTO role_permission_table
(
    role_id,
    permission_id
)
    SELECT role_info.id, permission_info.id FROM role_info, permission_info

ON CONFLICT DO NOTHING
;

Answer 6

如果您想避免两个子选择，可以像这样重写查询：

UPDATE table1
  SET col1 = o_min, col2 = o_max
FROM ( 
    SELECT min(ship_charge) as o_min, 
           max(ship_charge) as o_max
    FROM orders
) t 
WHERE col4 = 1001

如果ship_charge没有索引，这应该比两个子选择更快。如果ship_charge被索引，它可能不会产生很大的差异

---

编辑

从Postgres 9.5开始，这也可以写成：

UPDATE table1
  SET (col1, col2) = (SELECT min(ship_charge), max(ship_charge) FROM orders)
WHERE col4 = 1001

Answer 7

UPDATE table1
SET
    col1 = subquery.min_value,
    col2 = subquery.max_value
FROM
(

    SELECT
        1001 AS col4,
        MIN (ship_charge) AS min_value,
        MAX (ship_charge) AS max_value
    FROM orders
) AS subquery
WHERE table1.col4 = subquery.col4

如果您想一次更新 table1 中的多行，您还可以在子查询中返回多行。