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Here is another trick from Jerry,

SELECT a.id, a.warna FROM table_a a LEFT JOIN table_b b ON a.id = b.id WHERE b.id IS NULL OR a.warna<>b.warna;

is used for selecting data from table a which is not same like table b. Thanks Jerry.

Image by via CrunchBase

If you want to select value from table a that are not in table b, then you can use this query in mysql:

How do I select all rows in table `a` that is not in table `b`:

SELECT a.id FROM a LEFT JOIN b ON a.id = b.aid WHERE b.aid IS NULL;

a.id can be changed with value you use, example:

SELECT a.warna FROM a LEFT JOIN b ON a.warna = b.warna WHERE b.warna IS NULL;

Because “SELECT a.id” simply decides which fields will be output this will work just as well:

SELECT * FROM a LEFT JOIN b ON a.id = b.aid WHERE b.aid IS NULL;

Or

SELECT * FROM a LEFT JOIN b ON a.warna = b.warna WHERE b.warna IS NULL;

Another interesting posts:

• How adding another table to JOIN can improve performance ?
• JOIN Performance & Charsets
• How expensive is a WHERE clause in MySQL?