[英]MYSQL Select MAX Date inside a join statement
我正在嘗試返回記錄編號的歷史位置
我所擁有的是:
SELECT l.location, t.transaction_id, t.date_modified
FROM transactions as t
INNER JOIN (
SELECT
t1.received_id, t1.transaction_id, t1.date_modified
FROM (
SELECT received_id, MAX(date_modified) as maxmodify
FROM transactions
GROUP BY received_id) as max_record
JOIN transactions as t1
ON (t1.received_id =max_record.received_id)
) as whatever
INNER JOIN locations as l
ON l.location_id = t.location_id
INNER JOIN received as r
ON r.received_id = t.received_id
WHERE t.received_id='1782'
ORDER BY t.date_modified DESC
這大約需要 1 分鍾來解析並返回如下數據:
T-E1A 67294 2013-05-29 14:05:30
T-E1A 67293 2013-05-29 14:05:30
T-E1A 67294 2013-05-29 14:05:30
T-E1A 67293 2013-05-29 14:05:30
T-E1A 67294 2013-05-29 14:05:30
T-E1A 67293 2013-05-29 14:05:30
T-E1A 67294 2013-05-29 14:05:30
我真正希望看到的是來自這樣的查詢的數據:
SELECT l.location, t.transaction_id, t.date_modified FROM transactions as t
JOIN locations as l
ON l.location_id = t.location_id
JOIN received as r
ON r.received_id = t.received_id
WHERE t.received_id='1782'
ORDER BY t.date_modified DESC
哪個返回
T-E1A 67290 2013-05-29 13:58:26
T-E1A 67289 2013-05-29 13:58:26
ADJUST 67283 2013-04-26 11:33:54
ADJUST 67284 2013-04-26 11:33:54
ST10 67279 2013-04-26 09:52:41
ST10 67278 2013-04-26 09:52:13
ST10 67277 2013-04-26 09:50:58
ST10 67276 2013-04-26 09:50:20
SH3 67274 2013-04-26 09:49:39
第二個查詢更好,但我真的只想顯示每個記錄 ID 和位置的最后修改時間。
誰能看到我做錯了什么? 我很感激你的幫助。
像這樣的東西...
SELECT t1.received_id
, t1.transaction_id
, t1.date_modified
, l.location
FROM transactions t1
JOIN ( SELECT received_id, MAX(date_modified) maxmodify FROM transactions GROUP BY received_id) max_record
ON max_record.received_id = t1.received_id
AND max_record.maxmodify = t1.date_modified
JOIN locations l
ON l.location_id = t1.location_id
JOIN received r
ON r.received_id = t1.received_id
WHERE t1.received_id = '1782'
ORDER
BY t1.date_modified DESC
它的內核是這個……
SELECT x.*
FROM my_table x
JOIN (SELECT id,MAX(thing) max_thing FROM my_table GROUP BY id) y
ON y.id = x.id
AND y.max_thing = x.thing;
SELECT l.location, t.transaction_id, max(t.date_modified) FROM transactions as t
JOIN locations as l
ON l.location_id = t.location_id
JOIN received as r
ON r.received_id = t.received_id
WHERE t.received_id='1782'
group by l.location, t.transaction_id
ORDER BY t.date_modified DESC
這有幫助嗎?
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