SELECT pro.UserName, cla.ClassName, cla2.ClassName, pro.ProductName, pro.ProInfo, pro.PhotoUrl, pro.Price, pro.Address, pro.ProModel, pro.AddDate FROM (KS_EnterprisePro as pro LEFT JOIN KS_EnterPriseClass as cla ON pro.BigClassID = cla.ID) LEFT JOIN KS_EnterPriseClass as cla2 ON pro.SmallClassID = cla2.ID ORDER BY pro.Price DESC 上面语句还能再优化下吗?
在 ORDER BY pro.Price DESC 前面我加上 where pro.UserName like '%%' 查不出任何信息。 怎么解决。
pro.UserName='xxx' 这们可以
说明下你的两个表的关系,按道理where pro.UserName like '%%'相当于where pro.UserName is not null
至少有一条记录:pro.UserName字段数值:嘉达科技
SELECT pro.UserName, cla.ClassName, cla2.ClassName, pro.ProductName, pro.ProInfo, pro.PhotoUrl, pro.Price, pro.Address, pro.ProModel, pro.AddDate FROM (KS_EnterprisePro as pro LEFT JOIN KS_EnterPriseClass as cla ON pro.BigClassID = cla.ID) LEFT JOIN KS_EnterPriseClass as cla2 ON pro.SmallClassID = cla2.ID where pro.UserName like '%嘉达科技%' ORDER BY pro.Price DESC
下面可以查询出来
SELECT pro.UserName, cla.ClassName, cla2.ClassName, pro.ProductName, pro.ProInfo, pro.PhotoUrl, pro.Price, pro.Address, pro.ProModel, pro.AddDate FROM (KS_EnterprisePro as pro LEFT JOIN KS_EnterPriseClass as cla ON pro.BigClassID = cla.ID) LEFT JOIN KS_EnterPriseClass as cla2 ON pro.SmallClassID = cla2.ID where pro.UserName='嘉达科技' ORDER BY pro.Price DESC