Detailed explanation of replace into example in mysql

Detailed explanation of replace into example in mysql

replace into is similar to insert, except that replace into first tries to insert data into the table.

1. If it is found that this row of data already exists in the table (determined by the primary key or unique index), delete this row of data first, and then insert the new data.

2. Otherwise, insert new data directly.

Please note that the table into which data is inserted must have a primary key or a unique index! Otherwise, replace into will directly insert the data, which will result in duplicate data in the table.

There are three ways to write replace into in MySQL:

The code is as follows:

 replace into table(col, ...) values(...)
 replace into table(col, ...) select ...
 replace into table set col=value, ...

Extension: mysql gets the last primary key corresponding to the insertion (generally users get the primary key order number of the order table)

SELECT LAST_INSERT_ID() from dual

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