EXCLUSION CONSTRAINTS SQL Compatibility | MySQL, PostgreSQL, SQL Server, Oracle, SQLite

A generalization of UNIQUE constraints that uses arbitrary operators — most commonly used to prevent overlapping date/time ranges or spatial objects.

PostgreSQL constraint that ensures no two rows overlap in a specified way, using exclusion operators (e.g., cannot overlap in time). Implemented with a GiST index. Essential for scheduling systems where double-booking must be prevented.

Compatibility

SQL EXCLUSION CONSTRAINTS Compatibility Across Databases
Database System	Support Status	Since Version	Notes
MySQL	Not Supported	-	Not supported. Preventing overlapping ranges requires triggers or application logic.
PostgreSQL	Native	9.0	EXCLUDE USING index_method (col WITH op, ...). Uses GiST or SP-GiST indexes. The btree_gist extension is usually needed to mix btree-comparable columns (like INT) with range/geometric operators. Can use any operator with an appropriate operator class.
SQL Server	Not Supported	-	Not supported. Only UNIQUE and CHECK constraints available; overlap prevention requires triggers.
Oracle	Not Supported	-	Not supported. Only UNIQUE and CHECK constraints available.
SQLite	Not Supported	-	Not supported. Only UNIQUE and CHECK constraints available.

Details

Unique to PostgreSQL. Enables database-enforced non-overlap rules (e.g., no two reservations for the same room in the same time window) declaratively, without triggers or application checks.

Standard Syntax

CREATE TABLE bookings ( room INT, during TSRANGE, EXCLUDE USING gist (room WITH =, during WITH &&) );

Version Support

MySQL: Not supported PostgreSQL: Native since 9.0 SQL Server: Not supported Oracle: Not supported SQLite: Not supported

Per-Database Syntax & Notes

MySQL Alternative syntax

Not supported. Preventing overlapping ranges requires triggers or application logic.

-- Not supported.

PostgreSQL Native syntax

EXCLUDE USING index_method (col WITH op, ...). Uses GiST or SP-GiST indexes. The btree_gist extension is usually needed to mix btree-comparable columns (like INT) with range/geometric operators. Can use any operator with an appropriate operator class.

-- Prevent room double-booking: CREATE EXTENSION btree_gist; -- usually required CREATE TABLE bookings ( room INT, during TSRANGE, EXCLUDE USING gist (room WITH =, during WITH &&) ); -- No two rows can share the same room AND have overlapping time ranges.

SQL Server Alternative syntax

Not supported. Only UNIQUE and CHECK constraints available; overlap prevention requires triggers.

-- Not supported.

Oracle Alternative syntax

Not supported. Only UNIQUE and CHECK constraints available.

-- Not supported.

SQLite Alternative syntax

Not supported. Only UNIQUE and CHECK constraints available.

-- Not supported.