mysql query ignore duplicates code example

Example 1: select where duplicate mysql

SELECT 
    col1, COUNT(col1),
    col2, COUNT(col2)
FROM
    table_name
GROUP BY 
    col1, 
    col2
HAVING 
       (COUNT(col1) > 1) AND 
       (COUNT(col2) > 1);

Example 2: mysql on duplicate key ignore

INSERT INTO table_tags (tag) VALUES ('tag_a'),('tab_b'),('tag_c') ON DUPLICATE KEY UPDATE tag=tag;