So your saying that this code still produces the same result in with the same efficiency? (I took out another join and moved it to the where clause)

INSERT INTO Table5

SELECT DISTINCT

CD.Desc AS Desc,

SD.Num AS Num,

SD.Batch AS Batch,

CD.CodeId AS CodeId,

SD.Type AS Type,

CH.Id AS Id,

FROM Table1 SD

JOIN Table2 CH

ON CH.Num=SD.Num

JOIN Table3 M

ON M.Code=SD.Code

AND (Map=1 OR Map=@Map)

AND CH.Date1 BETWEEN M.Date2 AND M.Date3

JOIN Table4 CD

ON M.CodeId=CD.CodeId

WHERE SD.Code IS NOT NULL AND RTRIM(LTRIM(SD.Code ))<>''

AND CH.Batch = @Batch

AND CH.Flag= 0

AND SD.Batch = @Batch

AND SD.Flag= 0