Interview Q&A / SQL & DBMS

INTERVIEW Q&A · 69 QUESTIONS

SQL & DBMS interview questions

Joins, keys, normalisation, indexes and transactions for placement and backend interviews.

  1. What happens when a subquery used with = returns more than one row?

    The database raises an error such as "subquery returns more than 1 row", because = expects a single value. Use IN, ANY or ALL for multiple values, or make the subquery return one row with an aggregate or LIMIT.

    BeginnerQuick answer1 min read