Tuesday, August 05, 2008

NOT IN bisa diganti pake JOIN dan IS NULL

beberapa bulan yg lalu aku mendapatkan sebuah query yg lambat bgt, setelah googling ternyata permasalahannya ada di kondisi NOT IN, di situ dijelaskan kalo NOT IN bisa diganti pake JOIN dan IS NULL, contoh penggunaannya sbb

NOT IN


SELECT TABLE_A.COLUMN_A
FROM TABLE_A
WHERE TABLE_A.COLUMN_A NOT IN
(
SELECT TABLE_B.COLUMN_A
FROM TABLE_B
)


JOIN dan IS NULL


SELECT TABLE_A.COLUMN_A
FROM TABLE_A
LEFT JOIN TABLE_B
ON TABLE_A.COLUMN_A = TABLE_B.COLUMN_A
WHERE TABLE_B.COLUMN_A IS NULL


query ini udah ku coba di MSSQL dan Oracle, hasilnya bisa dieksekusi jauh lebih cepat

1 comment:

Anonymous said...

Good for people to know.