三表联合查询，按产地排序，并要求每个产地中有一个最低价格的sql语句
SELECT top 5 tc.Id,
tc.CottonLength,
tc.CottonMavalue,
tc.CottonStrength,
tc.CottonQuote,
tc.CottonType,
tc.CottonSailing,
CASE tc.CottonType WHEN '1' THEN '港口寄售' WHEN '0' THEN '远期交易' ELSE '' END AS TypeName,
tc.CottonCount,
tc.CottonRemark,
tsc2.[SysName] AS CottonArea,
tsc3.[SysName] AS CottonClass,
tsc4.[SysName] AS CottonYear,
tsc5.[SysName] AS CottonWarehouse
FROM dbo.T_Cotton tc
LEFT JOIN dbo.T_SysCode tsc2 ON tc.CottonArea =tsc2.Id
LEFT JOIN dbo.T_SysCode tsc3 ON tc.CottonClass=tsc3.Id
LEFT JOIN dbo.T_SysCode tsc4 ON tc.CottonYear = tsc4.Id
LEFT JOIN dbo.T_SysCode tsc5 ON tc.CottonWarehouse = tsc5.Id
LEFT JOIN dbo.T_Sale ts ON ts.CottonId=tc.Id
WHERE tc.Id in(
SELECT Id FROM T_Cotton WHERE
CottonQuote in (SELECT MIN(CottonQuote) FROM dbo.T_Cotton where UserId =1 AND tc.status<>0 group BY CottonArea))

[解决办法]