SELECT * fromtable_aGO SELECT * fromTable_bGO --Internal Connection SELECTA.*B.* fromTable_a AJOINTable_b B ona.ID=b.idSELECTA.*B.* fromTable_a AINNER JOINTable_b B ona.ID=b.idGO --the form of an internal connection equivalent direct multiple table from SELECTA.*B.* fromTable_a AINNER JOINTable_b B ona.ID=b.idSELECTA.*B.* fromTable_a A, Table_b BWHEREa.ID=b.id--left Connection SELECTA.*B.* fromTable_a A Left JOINTable_b B ona.ID=b.idSELECTA.*B.* fromTable_a A Left OUTER JOINTable_b B ona.ID=b.idGO --Right Connection SELECTA.*B.* fromTable_a A Right JOINTable_b B ona.ID=b.idSELECTA.*B.* fromTable_a A Right OUTER JOINTable_b B ona.ID=b.id--A left connection B is equivalent to B right connection a SELECTA.*B.* fromTable_a A Left JOINTable_b B ona.ID=b.idSELECTA.*B.* fromTable_b B Right JOINTable_a A ona.ID=b.id--Fully connected SELECTA.*B.* fromTable_a A Full JOINTable_b B ona.ID=b.idSELECTA.*B.* fromTable_a A Full OUTER JOINTable_b B ona.ID=b.id--A cross join without a WHERE clause will produce a Cartesian product of the table involved. SELECTA.*B.* fromTable_a A Cross JOINTable_b B--If you add a WHERE clause, the behavior of the cross join is similar to the inner join behavior SELECTA.*B.* fromTable_a A Cross JOINTable_b BWHEREa.ID=b.idSELECTA.*B.* fromTable_a AINNER JOINTable_b B ona.ID=b.ID
SQL Server r2--Internal connection left connection right connected full connected cross Connect