How to add a column and make it a foreign key in single MySQL statement?

Question

In mysql, can I add a column and foreign key in the same statement? And what is the proper syntax for adding the fk?

Here is my SQL:

ALTER TABLE dat         


        

Answer 1

The following query adds a column by alter query and the constraint query makes it a FK in a single mysql query. You can do it like this,

SYNTAX:

ALTER TABLE `SCHEMANAME`.`TABLE1` 
ADD COLUMN `FK_COLUMN` BIGINT(20) NOT NULL, 
ADD CONSTRAINT `FK_TABLE2_COLUMN` FOREIGN KEY (`FK_COLUMN`) 
REFERENCES `SCHEMANAME`.`TABLE2`(`PK_COLUMN`);

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EXAMPLE:

ALTER TABLE `USERDB`.`ADDRESS_TABLE` 
ADD COLUMN `USER_ID` BIGINT(20) NOT NULL AFTER `PHONE_NUMBER`, 
ADD CONSTRAINT `FK_CUSTOMER_TABLE_CUSTOMER_ID` FOREIGN KEY (`USER_ID`) 
REFERENCES `USERDB`.`CUSTOMER_TABLE`(`CUSTOMER_ID`);