求教一SQL优化
SELECT [SellID]
,[SortID]
,[Title]
FROM [TestSort].[dbo].[T_Sell] where title like '%测% '
and SellID IN (SELECT SellID FROM [T_Sell_Property] where ValueString= '黑色 ' AND LabelID=2)
一直说IN 效率不高， 可我现在有这样的需求，应该怎样优化呢？
[解决办法]
select a.* from
(
SELECT [SellID]
,[SortID]
,[Title]
FROM [TestSort].[dbo].[T_Sell] where title like '%测% '
) a,
(
SELECT SellID FROM [T_Sell_Property] where ValueString= '黑色 ' AND LabelID=2
) b
where a.SellID = b.SellID
[解决办法]
SELECT [SellID]
,[SortID]
,[Title]
FROM [TestSort].[dbo].[T_Sell] a join [T_Sell_Property] b
on a.title like '%测% ' and b.ValueString= '黑色 ' and b.LabelID=2 and a.SellID = b.SellID
[解决办法]
SELECT [SellID]
,[SortID]
,[Title]
FROM [TestSort].[dbo].[T_Sell] a where title like '%测% '
and SellID exists (SELECT * FROM [T_Sell_Property] where a.sellid=sellid and ValueString= '黑色 ' AND LabelID=2)
[解决办法]
刚才发的有点问题。。exists比in效率高，好多人都这么说，我没测试过，你可以试试。。
SELECT [SellID]
,[SortID]
,[Title]
FROM [TestSort].[dbo].[T_Sell] a where title like '%测% '
and exists (SELECT * FROM [T_Sell_Property] where a.sellid=sellid and ValueString= '黑色 ' AND LabelID=2)
[解决办法]
SELECT [SellID]
,[SortID]
,[Title]
FROM [TestSort].[dbo].[T_Sell] a，(SELECT SellID FROM [T_Sell_Property] where ValueString= '黑色 ' AND LabelID=2) b
where title like '%测% '
and a.SellID=b.SellID
