mysql - sql中没有重复代码

Question

我的 sql 语句有问题。它在我的符号代码上一定不能重复。我如何删除其他重复的符号代码？

 SELECT     TOP (10) dbo.ltb_stockinfo.**SymbolCode**, dbo.stockInfoPrices.ChangePercent
 FROM       dbo.ltb_stockinfo INNER JOIN
            dbo.stockInfoPrices ON dbo.ltb_stockinfo.ID = dbo.stockInfoPrices.SymbolListId
WHERE     (dbo.ltb_stockinfo.NSCMarketSegment = N'NO')
GROUP BY dbo.ltb_stockinfo.SymbolCode, dbo.stockInfoPrices.ChangePercent
ORDER BY dbo.stockInfoPrices.ChangePercent DESC

非常感谢!

Answer 1

你不必使用 max、min 甚至 sum

SELECT     TOP (10) dbo.ltb_stockinfo.SymbolCode, MAX(dbo.stockInfoPrices.ChangePercent)
 FROM       dbo.ltb_stockinfo INNER JOIN
            dbo.stockInfoPrices ON dbo.ltb_stockinfo.ID = dbo.stockInfoPrices.SymbolListId
WHERE     (dbo.ltb_stockinfo.NSCMarketSegment = N'NO')
GROUP BY dbo.ltb_stockinfo.SymbolCode
ORDER BY MAX(dbo.stockInfoPrices.ChangePercent) DESC