Interview Q&A / SQL & DBMS
SQL & DBMS interview questions
Joins, keys, normalisation, indexes and transactions for placement and backend interviews.
Prefer rapid revision? Practise SQL & DBMS short interview answers →
- What does SELECT DISTINCT do when you list more than one column?
DISTINCT removes duplicate rows, not duplicate values in one column. Two rows are duplicates only if every selected column is equal, and NULLs are treated as equal to each other.
BeginnerQuick answer1 min read