我有以下更新宣告：
UPDATE users u
SET last_login=(
SELECT created_on
FROM user_login_log log
WHERE log.user_id = u.id
ORDER BY log.created_on DESC
LIMIT 1
)
但是..如果我有更多需要更新的值怎么辦？我需要：
UPDATE users u
SET last_login=(
SELECT created_on
FROM user_login_log log
WHERE log.user_id = u.id
ORDER BY log.created_on DESC
LIMIT 1
),
last_ip=(
SELECT ip
FROM user_login_log log
WHERE log.user_id = u.id
ORDER BY log.created_on DESC
LIMIT 1
)
這看起來很貴。雖然找不到其他方法。
uj5u.com熱心網友回復：
一種方法是在單個運算式中更新兩列：
UPDATE users u
SET (last_login, last_ip) = (
SELECT created_on, ip
FROM user_login_log log
WHERE log.user_id = u.id
ORDER BY log.created_on DESC
LIMIT 1)
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標籤：sql PostgreSQL
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