The GROUP BY Clause

The GROUP BY clause can be used to create unique groups of data, to form aggregations, to remove duplicates and for other reasons.

For instance, you can count all books per author:

SQL	SqliteMagic
SELECT AUTHOR_ID, COUNT(*) FROM BOOK GROUP BY AUTHOR_ID	import static com.siimkinks.sqlitemagic.BookTable.BOOK; import static com.siimkinks.sqlitemagic.Select.count; CompiledSelect<Book, Select.SelectN> compiledSelect = Select .columns(BOOK.AUTHOR_ID, count()) .from(BOOK) .groupBy(BOOK.AUTHOR_ID) .compile();

Query created above can be used to define a SQL view, for example.

See Next

• TheSELECT Clause
• The FROM Clause
• The JOIN Clause
• The WHERE Clause
• The HAVING Clause
• The ORDER BY Clause
• The LIMIT .. OFFSET Clause
• Generated Tables
• Aliased Tables
• Nested Selects
• Column Expressions
• Conditional Expressions