Insert into a MySQL table or update if exists

I want to add a row to a database table, but if a row exists with the same unique key I want to update the row.

For example,

insert into table (id, name, age) values(1, "A", 19)

Let’s say the unique key is id, and in my database there is a row with id = 1. In that case I want to update that row with these values. Normally this gives an error. If I use insert IGNORE it will ignore the error, but it still won’t update.

 Answers

Use INSERT ... ON DUPLICATE KEY UPDATE

QUERY:

INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE    
name="A", age=19

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Try this out:

INSERT INTO table (id, name, age) VALUES (1, 'A', 19) ON DUPLICATE KEY UPDATE id = id + 1;

Hope this helps.

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When using batch insert use the following syntax:

INSERT INTO TABLE (id, name, age) VALUES (1, "A", 19), (2, "B", 17), (3, "C", 22)
ON DUPLICATE KEY UPDATE
    name = VALUES (name),
    ...

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When using SQLite:

REPLACE into table (id, name, age) values(1, "A", 19)

Provided that id is the primary key. Or else it just inserts another row. 

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INSERT INTO table (id, name, age) VALUES (1, 'A', 19) ON DUPLICATE KEY UPDATE id = id + 1;

Also do not forget to concern about the unique key constraint.

ALTER TABLE `table` ADD UNIQUE `unique_key` ( `id` )