[Solved] Which of the following SQL queries correctly finds duplicate email values in a table named users? — Ans: SELECT email FROM users GROUP BY email HAVING COUNT(*) > 1; | SQL

SQL - Advanced Query Patterns

Which of the following SQL queries correctly finds duplicate email values in a table named users?

ASELECT email FROM users GROUP BY email HAVING COUNT(*) > 1;

BSELECT email FROM users WHERE COUNT(email) > 1;

CSELECT email FROM users GROUP BY email WHERE COUNT(*) > 1;

DSELECT email FROM users HAVING COUNT(email) > 1;

Step-by-Step Solution

Solution:

Step 1: Check correct syntax for grouping and filtering
GROUP BY groups rows; HAVING filters groups. WHERE cannot filter aggregates.
Step 2: Identify correct query
SELECT email FROM users GROUP BY email HAVING COUNT(*) > 1; uses GROUP BY email and HAVING COUNT(*) > 1 correctly.
Final Answer:
SELECT email FROM users GROUP BY email HAVING COUNT(*) > 1; -> Option A
Quick Check:
GROUP BY + HAVING filters duplicates correctly [OK]

Quick Trick: Use HAVING, not WHERE, to filter grouped results [OK]

Common Mistakes:

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Which of the following SQL queries correctly finds duplicate email values in a table named users?