How can I check for duplicates before inserting into a table when inserting by select

Question

How can I check for duplicates before inserting into a table when inserting by select:

insert into table1
select col1, col2 
from table2

I need

Answer 1

You can simply add IGNORE into your insert statement.

e.g

INSERT IGNORE INTO table1
SELECT col1, col2 
FROM table2

This is discussed here