USE dating_app;

-- Existing users keep a NULL county until they submit an updated location.
SET @column_exists = (
    SELECT COUNT(*)
    FROM information_schema.columns
    WHERE table_schema = DATABASE()
      AND table_name = 'user_profiles'
      AND column_name = 'county'
);
SET @statement = IF(
    @column_exists = 0,
    'ALTER TABLE user_profiles ADD COLUMN county VARCHAR(120) NULL AFTER city',
    'SELECT 1'
);
PREPARE migration_statement FROM @statement;
EXECUTE migration_statement;
DEALLOCATE PREPARE migration_statement;