MySQL Query ~ data that exists in one table and not in another

A, b two tables, find the ID field, there is a table, but there is no data in table B. A total of 13w data, after the deduplication of about 3W data, b table has 2W data, and B table ID field is indexed.

Method One

Easy to understand with not in, low efficiency ~ Execution Time: 1.395 seconds ~

1 SELECT distinct a.id from  A where a.id not in (select ID from B)

Method Two

Use left Join...on ..., "b.id isnull" indicates a record of NULL in the b.ID field after you have connected-the execution time: 0.739 seconds ~

1 Select a.id from A left join B in a.id=b.id where b.id is null

Graphic

Method Three

Logic is relatively complex, but fastest ~ execution time: 0.570 seconds ~

1  SELECT * from  B 2     where (select COUNT (1) as Num from A where a.id = b.id) = 0

MySQL Query ~ data that exists in one table and not in another