alter table add column if not exists for code example
Example 1: add column if not exists
ALTER TABLE test ADD COLUMN IF NOT EXISTS column_a VARCHAR(255);
ALTER TABLE test MODIFY IF EXISTS column_a VARCHAR(255);
Example 2: sql alter table add column if exists
IF NOT EXISTS (
SELECT
*
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = 'table_name' AND COLUMN_NAME = 'col_name')
BEGIN
ALTER TABLE table_name
ADD col_name data_type NULL
END;