feat: add ClickHouse support to sqlc parse (#4267)

* feat: add ClickHouse database engine support

Add ClickHouse support using the github.com/sqlc-dev/doubleclick parser library.

New files in internal/engine/clickhouse/:
- parse.go: Parser implementation using doubleclick
- convert.go: AST converter from doubleclick to sqlc AST
- format.go: ClickHouse-specific SQL formatting
- catalog.go: Catalog initialization
- stdlib.go: Standard library functions
- reserved.go: Reserved keywords
- utils.go: Helper functions
- parse_test.go: Unit tests

Supported SQL operations:
- SELECT with JOINs, subqueries, CTEs, window functions
- INSERT with VALUES and SELECT subquery
- UPDATE and DELETE
- CREATE TABLE, ALTER TABLE, DROP TABLE, TRUNCATE

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: remove test file

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: return empty function set from stdlib

Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: move ClickHouse support to parse command only

Remove ClickHouse from compiler/engine.go and config.go.
Add --dialect clickhouse support to the sqlc parse command.

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: kyleconroy

go.mod

@@ -1,8 +1,6 @@
 module github.com/sqlc-dev/sqlc
 
-go 1.24.0
-
-toolchain go1.24.1
+go 1.24.7
 
 require (
 	github.com/antlr4-go/antlr/v4 v4.13.1
@@ -48,6 +46,7 @@ require (
 	github.com/pingcap/failpoint v0.0.0-20240528011301-b51a646c7c86 // indirect
 	github.com/pingcap/log v1.1.0 // indirect
 	github.com/rogpeppe/go-internal v1.10.0 // indirect
+	github.com/sqlc-dev/doubleclick v1.0.0 // indirect
 	github.com/stoewer/go-strcase v1.2.0 // indirect
 	github.com/wasilibs/wazero-helpers v0.0.0-20240620070341-3dff1577cd52 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f // indirect

go.sum

@@ -157,6 +157,8 @@ github.com/spf13/cobra v1.10.2/go.mod h1:7C1pvHqHw5A4vrJfjNwvOdzYu0Gml16OCs2GRiT
 github.com/spf13/pflag v1.0.9/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/spf13/pflag v1.0.10 h1:4EBh2KAYBwaONj6b2Ye1GiHfwjqyROoF4RwYO+vPwFk=
 github.com/spf13/pflag v1.0.10/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/sqlc-dev/doubleclick v1.0.0 h1:2/OApfQ2eLgcfa/Fqs8WSMA6atH0G8j9hHbQIgMfAXI=
+github.com/sqlc-dev/doubleclick v1.0.0/go.mod h1:ODHRroSrk/rr5neRHlWMSRijqOak8YmNaO3VAZCNl5Y=
 github.com/sqlc-dev/mysql v0.0.0-20251129233104-d81e1cac6db2 h1:kmCAKKtOgK6EXXQX9oPdEASIhgor7TCpWxD8NtcqVcU=
 github.com/sqlc-dev/mysql v0.0.0-20251129233104-d81e1cac6db2/go.mod h1:TrDMWzjNTKvJeK2GC8uspG+PWyPLiY9QKvwdWpAdlZE=
 github.com/stoewer/go-strcase v1.2.0 h1:Z2iHWqGXH00XYgqDmNgQbIBxf3wrNq0F3feEy0ainaU=

internal/cmd/parse.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"github.com/sqlc-dev/sqlc/internal/engine/clickhouse"
 	"github.com/sqlc-dev/sqlc/internal/engine/dolphin"
 	"github.com/sqlc-dev/sqlc/internal/engine/postgresql"
 	"github.com/sqlc-dev/sqlc/internal/engine/sqlite"
@@ -27,15 +28,18 @@ Examples:
   echo "SELECT * FROM users" | sqlc parse --dialect mysql
 
   # Parse SQLite SQL
-  sqlc parse --dialect sqlite queries.sql`,
+  sqlc parse --dialect sqlite queries.sql
+
+  # Parse ClickHouse SQL
+  sqlc parse --dialect clickhouse queries.sql`,
 	Args: cobra.MaximumNArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
 		dialect, err := cmd.Flags().GetString("dialect")
 		if err != nil {
 			return err
 		}
 		if dialect == "" {
-			return fmt.Errorf("--dialect flag is required (postgresql, mysql, or sqlite)")
+			return fmt.Errorf("--dialect flag is required (postgresql, mysql, sqlite, or clickhouse)")
 		}
 
 		// Determine input source
@@ -71,8 +75,11 @@ Examples:
 		case "sqlite":
 			parser := sqlite.NewParser()
 			stmts, err = parser.Parse(input)
+		case "clickhouse":
+			parser := clickhouse.NewParser()
+			stmts, err = parser.Parse(input)
 		default:
-			return fmt.Errorf("unsupported dialect: %s (use postgresql, mysql, or sqlite)", dialect)
+			return fmt.Errorf("unsupported dialect: %s (use postgresql, mysql, sqlite, or clickhouse)", dialect)
 		}
 		if err != nil {
 			return fmt.Errorf("parse error: %w", err)

internal/engine/clickhouse/catalog.go

@@ -0,0 +1,16 @@
+package clickhouse
+
+import (
+	"github.com/sqlc-dev/sqlc/internal/sql/catalog"
+)
+
+func NewCatalog() *catalog.Catalog {
+	def := "default" // ClickHouse default database
+	return &catalog.Catalog{
+		DefaultSchema: def,
+		Schemas: []*catalog.Schema{
+			defaultSchema(def),
+		},
+		Extensions: map[string]struct{}{},
+	}
+}