CODEWITHSUNDEEP
mysqlsqljoinunion
TheTom
TheTom

Reputation: 1044

MySql select by excluding all id from another table

I would like to select data from a table which looks like ID|FOO|CITY|BAR

there is another table where all data which has been selected yet will be stored so that I get unique results. This table looks like ID|ID_from_other_table

Now I'm stucking if I either should use a left join or a union? Which one is faster and, how can I set this up the correct way?

Upvotes: 0

Views: 90

Answers (1)

potashin
potashin

Reputation: 44581

left join would be probably faster in MySQL rather than other anti-join patterns like not in and not exists.

select t1.*
from table1 t1
left join table2 t2 on t1.id = t2.id_from_other_table
where t2.id is null

Upvotes: 1

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