how alter table in sql code example
Example 1: sql add column
ALTER TABLE Customers
ADD Email varchar(255);
Example 2: sql alter table
Adds, deletes or edits columns in a table. It can also be used to add and
delete constraints in a table, as per the above.
Example: Adds a new boolean column called ‘approved’ to a table named
‘deals’.
ALTER TABLE deals
ADD approved boolean;
Example 2: Deletes the ‘approved’ column from the ‘deals’ table
ALTER TABLE deals
DROP COLUMN approved;
Example 3: sql alter table
IF NOT EXISTS(SELECT 1 FROM sys.columns
WHERE Name = N'Email'
AND Object_ID = Object_ID(N'dbo.Customers'))
BEGIN
ALTER TABLE Customers
ADD Email varchar(255);
END