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據的集合，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。
2 回答
繁花如伊
TA貢獻2012條經驗 獲得超12個贊
兄弟，你這是mysql，開始被你誤導啦
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 |
子衿沉夜
TA貢獻1828條經驗 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：
第一把雙引號內部的雙引號轉義：
$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！
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