SQL Feature Support in CockroachDB v1.0

Making CockroachDB easy to use is a top priority for us, so we chose to implement SQL. However, even though SQL has a standard, no database implements all of it, nor do any of them have standard implementations of all features.

To understand which standard SQL features we support (as well as common extensions to the standard), use the table below.

• Component lists the components that are commonly considered part of SQL.
• Supported shows CockroachDB's level of support for the component.
• Type indicates whether the component is part of the SQL Standard or is an Extension created by ourselves or others.
• Details provides greater context about the component.

Features

Row Values

Component	Supported	Type	Details
Identifiers	✓	Standard	Identifiers documentation
INT	✓	Standard	INT documentation
FLOAT, REAL	✓	Standard	FLOAT documentation
BOOLEAN	✓	Standard	BOOL documentation
DECIMAL, NUMERIC	✓	Standard	DECIMAL documentation
NULL	✓	Standard	NULL-handling documentation
BYTES	✓	CockroachDB Extension	BYTES documentation
Automatic key generation	✓	Common Extension	SERIAL documentation
STRING, CHARACTER	✓	Standard	STRING documentation
COLLATE	✓	Standard	COLLATE documentation
AUTO INCREMENT	Alternative	Common Extension	SERIAL replaces support for this component.
Key-value pairs	Alternative	Extension	Key-Value FAQ
Arrays	Planned	Standard	GitHub Issue tracking array support
JSON	Planned	Common Extension	GitHub Issue tracking JSON support
XML	✗	Standard	XML data can be stored as BYTES, but we do not offer XML parsing.
UNSIGNED INT	✗	Common Extension	UNSIGNED INT causes numerous casting issues, so we do not plan to support it.
SET, ENUM	✗	MySQL, PostgreSQL Extension	Only allow rows to contain values from a defined set of terms.

Constraints

Component	Supported	Type	Details
Not Null	✓	Standard	Not Null documentation
Unique	✓	Standard	Unique documentation
Primary Key	✓	Standard	Primary Key documentation
Check	✓	Standard	Check documentation
Foreign Key	✓	Standard	Foreign Key documentation
Default Value	✓	Standard	Default Value documentation

Transactions

Component	Supported	Type	Details
Transactions (ACID semantics)	✓	Standard	Transactions documentation
BEGIN	✓	Standard	BEGIN documentation
COMMIT	✓	Standard	COMMIT documentation
ROLLBACK	✓	Standard	ROLLBACK documentation
SAVEPOINT	✓	CockroachDB Extension	While SAVEPOINT is part of the SQL standard, we only support our extension of it

Indexes

Component	Supported	Type	Details
Indexes	✓	Common Extension	Indexes documentation
Multi-column indexes	✓	Common Extension	We do not limit on the number of columns indexes can include
Covering indexes	✓	Common Extension	Storing Columns documentation
Multiple indexes per query	Planned	Common Extension	Use multiple indexes to filter the table's values for a single query
Full-text indexes	Planned	Common Extension	GitHub Issue tracking full-text index support
Prefix/Expression Indexes	Potential	Common Extension	Apply expressions (such as LOWER()) to values before indexing them
Geospatial indexes	Potential	Common Extension	Improves performance of queries calculating geospatial data
Hash indexes	✗	Common Extension	Improves performance of queries looking for single, exact values
Partial indexes	✗	Common Extension	Only index specific rows from indexed columns

Schema Changes

Component	Supported	Type	Details
ALTER TABLE	✓	Standard	ALTER TABLE documentation
Database renames	✓	Standard	RENAME DATABASE documentation
Table renames	✓	Standard	RENAME TABLE documentation
Column renames	✓	Standard	RENAME COLUMN documentation
Adding columns	✓	Standard	ADD COLUMN documentation
Removing columns	✓	Standard	DROP COLUMN documentation
Adding constraints	✓	Standard	ADD CONSTRAINT documentation
Removing constraints	✓	Standard	DROP CONSTRAINT documentation
Index renames	✓	Standard	RENAME INDEX documentation
Adding indexes	✓	Standard	CREATE INDEX documentation
Removing indexes	✓	Standard	DROP INDEX documentation

Statements

Component	Supported	Type	Details
Common statements	✓	Standard	SQL Statements documentation
UPSERT	✓	PostgreSQL, MSSQL Extension	UPSERT documentation
EXPLAIN	✓	Common Extension	EXPLAIN documentation
SELECT INTO	Alternative	Common Extension	You can replicate similar functionality using CREATE TABLE and then INSERT INTO ... SELECT ....

Clauses

Component	Supported	Type	Details
Common clauses	✓	Standard	SQL Grammar documentation
LIMIT	✓	Common Extension	Limit the number of rows a statement returns.
LIMIT with OFFSET	✓	Common Extension	Skip a number of rows, and then limit the size of the return set.
RETURNING	✓	Common Extension	Retrieve a table of rows statements affect.

Table Expressions

Component	Supported	Type	Details
Table and View references	✓	Standard	Table expressions documentation
AS in table expressions	✓	Standard	Aliased table expressions documentation
JOIN (INNER, LEFT, RIGHT, FULL, CROSS)	Functional	Standard	Join expressions documentation
Sub-queries as table expressions	Partial	Standard	Non-correlated subqueries are supported; correlated are not.
Table generator functions	Partial	PostgreSQL Extension	Table generator functions documentation
WITH ORDINALITY	✓	CockroachDB Extension	Ordinality annotation documentation

Value Expressions and Boolean Formulas

Component	Supported	Type	Details
Common functions	✓	Standard	Functions calls and SQL special forms documentation
Common operators	✓	Standard	Operators documentation
IF/CASE/NULLIF	✓	Standard	Conditional expressions documentation
COALESCE/IFNULL	✓	Standard	Conditional expressions documentation
AND/OR/NOT	✓	Standard	Logical operators documentation
LIKE/ILIKE	✓	Standard	String pattern matching documentation
SIMILAR TO	✓	Standard	SQL regexp pattern matching documentation
Matching using POSIX regular expressions	✓	Common Extension	POSIX regexp pattern matching documentation
EXISTS	Partial	Standard	Non-correlated subqueries are supported; correlated are not. Currently works only with small data sets.
Scalar subqueries	Partial	Standard	Non-correlated subqueries are supported; correlated are not. Currently works only with small data sets.
Bitwise arithmetic	✓	Common Extension	Operators documentation
Array constructors and subscripting	Partial	PostgreSQL Extension	Array expression documentation: Constructor syntax and Subscripting
COLLATE	✓	Standard	Collation expressions documentation
Column ordinal references	✓	CockroachDB Extension	Column references documentation
Type annotations	✓	CockroachDB Extension	Type annotations documentation

Permissions

Component	Supported	Type	Details
Users	✓	Standard	GRANT documentation
Privileges	✓	Standard	Privileges documentation

Miscellaneous

Component	Supported	Type	Details
Column families	✓	CockroachDB Extension	Column Families documentation
Interleaved tables	✓	CockroachDB Extension	Interleaved Tables documentation
Information Schema	✓	Standard	Information Schema documentation
Views	✓	Standard	Views documentation
Window functions	✓	Standard	Window Functions documentation
Common Table Expressions	Planned	Common Extension	Also known as CTEs or WITH clauses. GitHub issue tracking common table expressions support.
Stored Procedures	Planned	Common Extension	Execute a procedure explicitly.
Cursors	✗	Standard	Traverse a table's rows.
Triggers	✗	Standard	Execute a set of commands whenever a specified event occurs.
Sequences	✗	Common Extension	Create a numeric sequence. Given CockroachDB's distributed architecture, sequences would be expensive. For fast, globally unique key generation, see SERIAL.