How to DROP multiple columns with a single ALTER TABLE statement in SQL Server?

Executing bulk column removal

The ALTER TABLE magic

Metadata alterations, specifically removing several columns from a SQL Server database table, is easily executed through the ALTER TABLE command. It's like taking out unnecessary fillings from your pizza—lessens the toppings overload and enhances the flavor.

Reclaiming Space after the drop

After dropping columns from SQL Server, especially fixed-length columns, occupied space isn't auto-reclaimed. It's the digital equivalent of cleaning up after a renovation—the debris isn't magically gone. To free up that space:

ALTER TABLE YourTable
DROP COLUMN Column1, Column2, Column3;
ALTER TABLE YourTable REBUILD; -- "Time for a spring cleaning!"
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A heads-up: this may be slow on large datasets, akin to cleaning a mansion versus a studio apartment. So, plan accordıngly!

SQL dialect differences

Yes, SQL too has dialects! In MySQL and PostgreSQL, you'd utter the DROP command like this:

ALTER TABLE YourTable
DROP COLUMN Column1,
DROP COLUMN Column2,
DROP COLUMN Column3;
-- "Opaque rules committee strikes again!"
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Each DROP COLUMN is a separate decree.

For Oracle, you group the culprits as follows:

ALTER TABLE YourTable
DROP (Column1, Column2, Column3);
-- "Oracle likes its drop operations served in parentheses."
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Nailing it with ALTER TABLE

Syntactic precision

SQL Server offers a highly optimized syntax for dropping multiple columns at once. Following this precise syntax ensures error-free execution, reduces redundancy, and improves code tidiness.

Constraint handling

Alongside dropping columns, SQL Server allows you to simultaneously drop constraints linked to the columns. Fancy term for saying—removing conditional dependencies between columns.

ALTER TABLE YourTable
DROP COLUMN Column1, Column2, 
DROP CONSTRAINT FK_YourTable_Column1;
-- "The less constraints in my life, the better!"
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Keep in mind, dropping constraints could affect relational integrity. Sever links wisely!

Official documentation

Armor yourself with the DBMS manual for detailed drop operations and precautions. Official documentation, such as MySQL's ALTER TABLE guide, serves as your authoritative companion for understanding syntax specifics and corner cases.