SQL DISTINCT vs GROUP BY: When to Use Each
By Sharon Ben-Moshe · August 21, 2026 · 2 min read
Sharon Ben-Moshe is the founder of sqlfmt, a browser-based SQL formatter and validator with misspelled-keyword suggestions across PostgreSQL, MySQL, SQLite, SQL Server, and BigQuery.
DISTINCT removes duplicate result rows; GROUP BY creates groups for aggregation. Learn the practical difference, examples, and common query mistakes.
Quick answer
Use SELECT DISTINCT to return unique result rows. Use GROUP BY when rows must form groups for an aggregate such as COUNT, SUM, or AVG. A GROUP BY without aggregates can resemble DISTINCT, but DISTINCT communicates deduplication directly while GROUP BY communicates grouping work.
FAQs
Can GROUP BY replace DISTINCT?
A GROUP BY on the same selected expressions can produce a unique-looking list, but DISTINCT is usually clearer when deduplication is the only goal. GROUP BY is the right tool when groups feed aggregate calculations.
Does DISTINCT work on multiple columns?
Yes. DISTINCT considers the complete selected row. `SELECT DISTINCT city, country` returns unique city-and-country combinations, not a separate unique list for each column.
When should I use GROUP BY in SQL?
Use GROUP BY when a query needs one result per group and aggregates such as COUNT, SUM, AVG, MIN, or MAX summarize the rows in each group.
Is DISTINCT faster than GROUP BY?
There is no universal answer. The optimizer, data distribution, indexes, selected expressions, and database version all affect the plan. Choose the clause that states the correct semantics, then inspect and measure the target query.
Keep reading
SQL BETWEEN Is Inclusive: Safer Date Range Queries
By Sharon Ben-Moshe · Aug 21, 2026
SQL BETWEEN includes both endpoints. Learn the timestamp boundary trap and use half-open date ranges that stay correct across databases.
Read postSQL DELETE vs TRUNCATE vs DROP: Choose Safely
By Sharon Ben-Moshe · Aug 21, 2026
DELETE removes selected rows, TRUNCATE empties a table, and DROP removes the table itself. Learn the crucial differences before running destructive SQL.
Read postTry it now
Paste your SQL into sqlfmt — format, validate, and catch typos free in your browser.