i have 3 tables
t1==>
t1.ID t1.co1 t1.col2 1 a b 2 a b t2==>
t2.ID t2.co1 t2.col2 1 a b 2 a b t3==>
t3.ID t3.co1 t3.col2 1 a b 2 a b i want inner join between all three tables using Linq and want selected column in 4th datatable.
equivalent sql query:
SELECT t1.ID,t2.col1,t3.col2 FROM t1 INNER JOIN t2 ON t1.ID=t2.ID INNER JOIN t3 ON t1.ID=t3.ID t4==>
t1.ID t2.co1 t3.col2 1 a b 2 a b Something like this
var Result = from row1 in t1 join row2 in t2 on row1.ID equals row2.ID join row3 in t3 on row1.ID equals row3.ID select new { ID = row1.ID, Col1 = row2.col1, Col2 = row3.col2 } DataTable dt = Result.CopyToDataTable(); 
CopyToDataTable() method.
Use LoadDataRow() to get a DataTable from an anonymous type as here. Else Result.CopyToDataTable().
//Get the column list as same as table1 to new datatable DataTable table4 = table1.Clone(); var Result = from x in t1.AsEnumerable() join y in t2.AsEnumerable() on x.Field<int>("ID") equals y.Field<int>("ID") join z in t3.AsEnumerable() on x.Field<int>("ID") equals z.Field<int>("ID") select new table4.LoadDataRow( new object[] { x.ID, y.col1, z.col2 }, false); 