The REPLACE statement in MySQL is used to insert or update a record into a table. If the record already exists in the table, it will be replaced by the new record, otherwise a new record will be inserted.
The REPLACE statement works in a similar way to the INSERT INTO statement. The syntax of the REPLACE statement is as follows:
REPLACE INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);
In this syntax, table_name is the name of the table where you want to insert or update the record, and (column1, column2, column3, ...) is a comma-separated list of the columns that you want to insert data into.
The VALUES clause is used to specify the values that you want to insert into the table. If a record with the same primary key or unique index as the new record already exists, the existing record will be deleted and replaced with the new record. If no record with the same primary key or unique index as the new record exists, a new record will be inserted.
For example, let’s assume that we have a table named employees with columns id, name, age, and salary. We can use the REPLACE statement to insert or update a record in the table as follows:
REPLACE INTO employees (id, name, age, salary) VALUES (1, 'John', 30, 5000);
If there is already a record in the employees table with id equal to 1, that record will be updated with the new values of name, age, and salary. Otherwise, a new record will be inserted with the specified values.
