MySQL 如果不存在，则更改表添加列

Question

i have error with my if. ERROR is "IF" is not valid in this position, expecting EOF, ALTER, ANALYZE...

my code looks like this can you help me please:)

IF NOT EXISTS (
  SELECT
    1
  FROM
    INFORMATION_SCHEMA.COLUMNS
  WHERE
    TABLE_NAME = 'clients' AND COLUMN_NAME = 'dateOfRegister')
BEGIN
  ALTER TABLE realestate
    ADD dateOfRegister DATE NOT NULL
END;

Answer 1

add delimter like this to your request.

delimiter |
IF NOT EXISTS (
  SELECT
    1
  FROM
    INFORMATION_SCHEMA.COLUMNS
  WHERE
    TABLE_NAME = 'clients' AND COLUMN_NAME = 'dateOfRegister')
BEGIN
  ALTER TABLE realestate ADD dateOfRegister DATE NOT NULL;
END;
delimiter ;

but it seems that your request will not do what you want to do. it is better to create a procedure or a function.