How to Add a Column in SQL Server
Last updated July 25, 2026 · By the SaturnSQL team
Use ALTER TABLE ... ADD with the column definition; SQL Server does not use the COLUMN keyword for ADD. A NOT NULL column needs a DEFAULT so existing rows get a value.
ALTER TABLE orders ADD discount DECIMAL(5,2) NOT NULL DEFAULT 0;Add several columns at once
ALTER TABLE orders ADD
coupon_code VARCHAR(30) NULL,
updated_at DATETIME2 NULL;Adding a nullable column, or a NOT NULL column with a default on recent versions, is a metadata-only change and completes instantly even on large tables.
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