mysql select from table1 that are not in table2

Hello experts
My problem is:
I need to make a selection from table USER whose id is not in table BLOCKED



USER(id:int, username:String)
BLOCKED(user1id:int, user2id:int)

something like

SELECT * from user, blocked WHERE user.id<>Blocked.id

It must be optimized: It seems NOT IN is too CPU greedy

regards



yarekGmailAsked:
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Guy Hengel [angelIII / a3]Billing EngineerCommented:
this query will do:


SELECT u.* from user u
LEFT JOIN blocked b
  ON u.id = b.id
WHERE b.id IS NULL

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0
Guy Hengel [angelIII / a3]Billing EngineerCommented:
alternative (both suggestions will require a index on blocked.id to be effective):
SELECT u.* from user u
WHERE NOT EXISTS( SELECT NULL FROM blocked b WHERE u.id = b.id )

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Mehul_PanchalCommented:
SELECT u.* from user u
LEFT JOIN blocked b
  ON u.id = b.id
WHERE b.id IS NULL
0

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