How does mysql determine if the data does not exist and then insert it?

Question

When inserting data, can we combine the following requirements into one sql statement?

1, determine whether the data exists;

2, there is no insertion;

3, then query the id field value of the data

Answer 1

Probably not possible, you have to do two queries separately, one query and one insert. Unless you call a stored procedure. The stored procedure should be able to achieve your needs

Answer 2

Use insert if not exists

INSERT INTO table(field1, field2, fieldn) SELECT 'field1', 'field2', 'fieldn' FROM DUAL WHERE NOT EXISTS(SELECT field FROM table WHERE field = ?)

Answer 3

MySQL, please use the powerful REPLACE INTO

Answer 4

Mysql can use REPLACE INTO, but it must have a unique index as a condition, but I have not used this, I feel it is more reliable to do it step by step