Tsql supports multi-column in Multi-column matching in Oracle.

Expected results: (I got a one-to-one relationship and compared it to another table) Select * From empoylee where (address1, address2) in (select address1, address2from empoyleeadresseswhere Country = 'Canada ') the preceding method cannot be used. You can also select * from (select (zcbm |', '| fwbm), which is slow) as T from t_fwzc) TT where T not in (select (zcbm | ',' | fwbm) as C from t_zc_fc_gx) solution 1: Use exists to determine select. * From empoylee awhere exists (select 'A' from empoyleeadresses B where B. count Ry = 'Canada 'and. address1 = B. address1 and. address2 = B. address2) solution 2: Use the inner join link to select * fromempoyleeinner join empoyleeadressesonempoylee. address1 = empoyleeadresses. address1andempoylee. address2 = empoyleeadresses. address2whereempoyleeadresses. country = 'Canada ') Select * fromempoylee eminner join empoyleeadresses emaonem. address1 = EMA. address1andem. address2 = EMA. address2andema. country = 'Canada 'Solution Solution 3: Associate the table with select. * From empoylee A, (select address1, address2 from empoyleeadresses where country = 'Canada ') bwherea. address1 = B. address1anda. address2 = B. address2 subjective perception solution 1 is faster. Objectively, you have not used "show Execution Plan" in the query analyzer to check which method is more efficient. for a delete statement, the statement is written as follows: delete from empoylee where exists (select 'A' from empoyleeadresses B where B. country = 'Canada 'and empoylee. address1 = B. address1 and empoylee. address2 = B. address2) Note delete fr Aliases cannot be used for tables after om ~