seniorT-SQL

What is MERGE statement and why is it controversial?

Updated May 17, 2026

Short answer

MERGE performs insert, update, and delete in a single statement.

Deep explanation

MERGE allows synchronizing two tables but has concurrency and bug-related concerns in SQL Server history. Many teams prefer separate INSERT/UPDATE statements for reliability.

Unlock with a Pro subscription to view this section.

View pricing

Real-world example

No real-world example available yet.

Unlock with a Pro subscription to view this section.

Upgrade to Pro

Common mistakes

No common mistakes listed yet.

Unlock with a Pro subscription to view this section.

Upgrade to Pro

Follow-up questions

No follow-up questions available yet.

Unlock with a Pro subscription to view this section.

Upgrade to Pro

More T-SQL interview questions

View all →