Inner join跟outer join的区别

DECLARE @TB1 TABLE(A INT,B INT)INSERT @TB1SELECT 1,2 UNION ALLSELECT 1,3DECLARE @TB2 TABLE(A INT,B INT)INSERT @TB2SELECT 1,2 SELECT * FROM @TB1 T1 INNER JOIN @TB2 T2 ON T1.A=T2.A and t1.b=t2.bSELECT * FROM @TB1 T1 full outer  JOIN @TB2 T2 ON T1.A=T2.A and t1.b=t2.b（所影响的行数为 2 行）（所影响的行数为 1 行）A           B           A           B           ----------- ----------- ----------- ----------- 1           2           1           2（所影响的行数为 1 行）A           B           A           B           ----------- ----------- ----------- ----------- 1           2           1           21           3           NULL        NULL（所影响的行数为 2 行）