Interview Q&A / SQL & DBMS
SQL & DBMS interview questions
Joins, keys, normalisation, indexes and transactions for placement and backend interviews.
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- What is the difference between a correlated and a non-correlated subquery?
A non-correlated subquery runs once and does not refer to the outer query. A correlated subquery refers to a column of the outer row, so it is evaluated once for each outer row, at least logically.
IntermediateQuick answer1 min read