Database Support

Database and source support matrix with dialect differences and important boundaries.

Core support

Source	Status	Notes
PostgreSQL	Supported	Broadest SQL feature coverage
MySQL / MariaDB	Supported	Linear mutation strategy
SQLite	Supported	Local/dev and embedded use
SQL Server	Supported	Dialect-specific limit/offset and JSON handling
Oracle	Supported	Boolean/function return types need care
MongoDB	Supported	JSON DSL to aggregation pipeline
Snowflake	Supported	Warehouse dialect surface
Redshift	Supported	Analytics-oriented SQL
ClickHouse	Configured source	Use with feature-specific validation
Filesystems	Supported	Local/S3/GCS virtual tables
OpenAPI	Supported for selected GETs	Remote fields and joins
CodeSQL	Supported	Source-code index tables

Dialect rule

Do not rely on implicit ordering. If a test or API response depends on order, specify order_by.

GraphQL

query {
  products(limit: 5, order_by: { id: asc }) {
    id
    name
  }
}

This is not a style preference. SQL result ordering is undefined without ORDER BY, so adding implicit ordering in a dialect would add cost and hide a client/test bug.

Feature boundaries

Some features differ by dialect: JSON aggregation, recursive CTE syntax, boolean representation, function return types, and MongoDB aggregation support.

Feature	Important boundary
JSON aggregation	SQL dialects render different aggregate functions; MongoDB uses native documents and a JSON DSL.
Recursive relationships	PostgreSQL/MySQL/SQLite use `WITH RECURSIVE`; Oracle/MSSQL do not use the `RECURSIVE` keyword.
Boolean values	Oracle and SQL Server may need JSON conversion or explicit return-type config for boolean-like function results.
Geo filters	PostGIS-style SQL and MongoDB `near` have different backend operators.
Analytics directives	Window rendering is dialect-specific and unsupported dialects should fail clearly.
Cursor pagination	Cursor fields are root-level synthetic fields and cursor strings are opaque.

Verified by TestAnalytics_DialectUnsupported core/internal/psql/window_test.go:106

Verified by TestQueryDSLParsing mongodriver/driver_test.go:17

Test command map

Shell

./scripts/test-postgres.sh
./scripts/test-mysql.sh
./scripts/test-sqlite.sh
./scripts/test-mongo.sh
./scripts/test-snowflake.sh

Docs-only edits do not need the full dialect matrix, but compiler or shared query-planning changes should run the affected dialect scripts.