基本上，我想这样做:
update vehicles_vehicle v
join shipments_shipment s on v.shipment_id=s.id
set v.price=s.price_per_vehicle;
我很确定这在MySQL(我的背景)中可以工作，但在postgres中似乎不起作用。我得到的错误是:
ERROR: syntax error at or near "join"
LINE 1: update vehicles_vehicle v join shipments_shipment s on v.shi...
^
当然有一个简单的方法来做到这一点，但我找不到合适的语法。那么，我该如何在PostgreSQL中写这个呢?
当前回答
——目标:使用join (postgres)更新选定的列——
UPDATE table1 t1
SET column1 = 'data'
FROM table1
RIGHT JOIN table2
ON table2.id = table1.id
WHERE t1.id IN
(SELECT table2.id FROM table2 WHERE table2.column2 = 12345)
其他回答
下面是一个简单的SQL，使用Name中的Middle_Name字段更新Name3表中的Mid_Name:
update name3
set mid_name = name.middle_name
from name
where name3.person_id = name.person_id;
开始吧:
update vehicles_vehicle v
set price=s.price_per_vehicle
from shipments_shipment s
where v.shipment_id=s.id;
我能做到的最简单。
第一种方式比第二种方式慢。
第一:
DO $$
DECLARE
page int := 10000;
min_id bigint; max_id bigint;
BEGIN
SELECT max(id),min(id) INTO max_id,min_id FROM opportunities;
FOR j IN min_id..max_id BY page LOOP
UPDATE opportunities SET sec_type = 'Unsec'
FROM opportunities AS opp
INNER JOIN accounts AS acc
ON opp.account_id = acc.id
WHERE acc.borrower = true
AND opp.sec_type IS NULL
AND opp.id >= j AND opp.id < j+page;
COMMIT;
END LOOP;
END; $$;
第二:
DO $$
DECLARE
page int := 10000;
min_id bigint; max_id bigint;
BEGIN
SELECT max(id),min(id) INTO max_id,min_id FROM opportunities;
FOR j IN min_id..max_id BY page LOOP
UPDATE opportunities AS opp
SET sec_type = 'Unsec'
FROM accounts AS acc
WHERE opp.account_id = acc.id
AND opp.sec_type IS NULL
AND acc.borrower = true
AND opp.id >= j AND opp.id < j+page;
COMMIT;
END LOOP;
END; $$;
我举个例子再解释一下。
任务:正确的信息，在哪里abiturients(即将离开中学的学生)提交申请大学早于他们获得学校证书(是的，他们获得证书早于他们颁发的证书(指定证书日期)。因此，我们将增加申请提交日期，以适应证书颁发日期。
因此。下一个mysql类语句:
UPDATE applications a
JOIN (
SELECT ap.id, ab.certificate_issued_at
FROM abiturients ab
JOIN applications ap
ON ab.id = ap.abiturient_id
WHERE ap.documents_taken_at::date < ab.certificate_issued_at
) b
ON a.id = b.id
SET a.documents_taken_at = b.certificate_issued_at;
以这样的方式变得像postgresql
UPDATE applications a
SET documents_taken_at = b.certificate_issued_at -- we can reference joined table here
FROM abiturients b -- joined table
WHERE
a.abiturient_id = b.id AND -- JOIN ON clause
a.documents_taken_at::date < b.certificate_issued_at -- Subquery WHERE
可以看到，原来的子查询JOIN的ON子句已经变成了WHERE条件之一，由AND与其他子查询连接，这些子查询已经从子查询中移动，没有任何变化。并且不再需要将表与自身连接(就像在子查询中那样)。
第一个表名:tbl_table1 (tab1)。 第二表名:tbl_table2 (tab2)。
将tbl_table1的ac_status列设置为“INACTIVE”
update common.tbl_table1 as tab1
set ac_status= 'INACTIVE' --tbl_table1's "ac_status"
from common.tbl_table2 as tab2
where tab1.ref_id= '1111111'
and tab2.rel_type= 'CUSTOMER';
