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查詢23號到28號中每天的最后一條數(shù)據(jù)的集，該如何操作？

MySQL SQL Server

寶慕林4294392 2022-04-06 10:07:12

　CREATE TABLE mytable(　　id INT PRIMARY KEY AUTO_INCREMENT,　　myvalue VARCHAR(10),　　mydate DATETIME　　)　　INSERT INTO mytable(myvalue,mydate) VALUES('a','2014-07-22 14:23:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('b','2014-07-22 15:28:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('c','2014-07-23 11:23:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('d','2014-07-25 14:23:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('f','2014-07-26 07:23:00');INSERT INTO mytable(myvalue,mydate) VALUES('e','2014-07-25 19:26:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('g','2014-07-27 14:23:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('h','2014-07-27 15:23:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('i','2014-07-27 19:51:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('k','2014-07-28 14:23:00');　　INSERT INTO mytable(myvalue,mydate) VALUES('l','2014-07-29 14:23:00');--查詢23號到28號中每天的最后一條數(shù)據(jù)的集合，即從這張表中篩選出myvalue為c、e、f、i、k哎呀，想寫個sql真是太難了，心好累。

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2 回答

當(dāng)年話下

TA貢獻(xiàn)1890條經(jīng)驗(yàn) 獲得超9個贊

select a.* from mytable a,(select date(mydate) mydate,max(mydate) max_datetime from mytable where date(mydate) between '2014-07-23' and '2014-07-28' group by date(mydate)) bwhere a.mydate=b.max_datetimeand date(a.mydate)=b.mydate

反對回復(fù) 2022-04-11

德瑪西亞99

TA貢獻(xiàn)1770條經(jīng)驗(yàn) 獲得超3個贊

$mysqli->query("SELECT answer FROM FAQ WHERE question="hello"")這句里面出錯了，修改的辦法有2種：
第一把雙引號內(nèi)部的雙引號轉(zhuǎn)義：
$mysqli->query("SELECT answer FROM FAQ WHERE question=\"hello\"");第二種把雙引號變成單引號：
$mysqli->query("SELECT answer FROM FAQ WHERE question='hello'");希望對你有所幫助！

反對回復(fù) 2022-04-11