feat(clickhouse): add ClickHouse database engine support

CLAUDE.md

@@ -87,9 +87,45 @@ Test the connection:
 mysql -h 127.0.0.1 -u root -pmysecretpassword -e "SELECT VERSION();"
 ```
 
-### Step 4: Run End-to-End Tests
+### Step 4: Install ClickHouse (Optional - for ClickHouse tests)
 
-With both databases running, the test framework automatically detects them:
+ClickHouse is required for ClickHouse engine tests. The ClickHouse feature is experimental and requires the `SQLCEXPERIMENT=clickhouse` flag.
+
+**Important:** Use the official ClickHouse repository, not the Ubuntu package (which has an old incompatible version).
+
+```bash
+# Add ClickHouse official repository key and source
+curl -fsSL https://packages.clickhouse.com/rpm/lts/repodata/repomd.xml.key | sudo gpg --dearmor -o /usr/share/keyrings/clickhouse-keyring.gpg
+ARCH=$(dpkg --print-architecture)
+echo "deb [signed-by=/usr/share/keyrings/clickhouse-keyring.gpg arch=${ARCH}] https://packages.clickhouse.com/deb stable main" | sudo tee /etc/apt/sources.list.d/clickhouse.list
+
+# Install ClickHouse from official repo
+sudo apt-get update
+sudo DEBIAN_FRONTEND=noninteractive apt-get install -y clickhouse-server clickhouse-client
+
+# Start ClickHouse server
+sudo clickhouse start
+```
+
+Test the connection:
+
+```bash
+clickhouse-client --query "SELECT version()"
+```
+
+The native database support automatically detects ClickHouse and uses:
+- URI: `clickhouse://default:@localhost:9000/default`
+- User: `default` (no password)
+- Port: 9000
+
+**Note:** ClickHouse tests require setting the experiment flag:
+```bash
+SQLCEXPERIMENT=clickhouse go test ./internal/endtoend -run "TestReplay/clickhouse" -v
+```
+
+### Step 5: Run End-to-End Tests
+
+With the databases running, the test framework automatically detects them:
 
 ```bash
 # Run all end-to-end tests
@@ -103,11 +139,12 @@ go test --tags=examples -timeout 20m ./...
 ```
 
 The native database support (in `internal/sqltest/native/`) automatically:
-- Detects running PostgreSQL and MySQL instances
+- Detects running PostgreSQL, MySQL, and ClickHouse instances
 - Starts services if installed but not running
 - Uses standard connection URIs:
   - PostgreSQL: `postgres://postgres:postgres@127.0.0.1:5432/postgres?sslmode=disable`
   - MySQL: `root:mysecretpassword@tcp(127.0.0.1:3306)/mysql`
+  - ClickHouse: `clickhouse://default:@localhost:9000/default`
 
 ### Running Tests
 
@@ -193,6 +230,11 @@ The `docker-compose.yml` provides test databases:
   - Password: `mysecretpassword`
   - Database: `dinotest`
 
+- **ClickHouse** - Port 9000 (experimental, requires `SQLCEXPERIMENT=clickhouse`)
+  - User: `default`
+  - Password: (none)
+  - Database: `default`
+
 ### Managing Databases
 
 ```bash
@@ -291,6 +333,7 @@ POSTGRESQL_SERVER_URI="postgres://postgres:mysecretpassword@localhost:5432/postg
   - `/postgresql/` - PostgreSQL parser and converter
   - `/dolphin/` - MySQL parser (uses TiDB parser)
   - `/sqlite/` - SQLite parser
+  - `/clickhouse/` - ClickHouse parser (uses doubleclick parser, experimental)
 - `/internal/compiler/` - Query compilation logic
 - `/internal/codegen/` - Code generation for different languages
 - `/internal/config/` - Configuration file parsing

docker-compose.yml

@@ -19,3 +19,14 @@ services:
       POSTGRES_DB: postgres
       POSTGRES_PASSWORD: mysecretpassword
       POSTGRES_USER: postgres
+
+  clickhouse:
+    image: "clickhouse/clickhouse-server:latest"
+    ports:
+      - "9000:9000"
+      - "8123:8123"
+    restart: always
+    environment:
+      CLICKHOUSE_DB: default
+      CLICKHOUSE_USER: default
+      CLICKHOUSE_PASSWORD: mysecretpassword

go.mod

@@ -1,10 +1,9 @@
 module github.com/sqlc-dev/sqlc
 
-go 1.24.0
-
-toolchain go1.24.1
+go 1.24.7
 
 require (
+	github.com/ClickHouse/clickhouse-go/v2 v2.42.0
 	github.com/antlr4-go/antlr/v4 v4.13.1
 	github.com/cubicdaiya/gonp v1.0.4
 	github.com/davecgh/go-spew v1.1.1
@@ -22,6 +21,7 @@ require (
 	github.com/riza-io/grpc-go v0.2.0
 	github.com/spf13/cobra v1.10.2
 	github.com/spf13/pflag v1.0.10
+	github.com/sqlc-dev/doubleclick v0.0.0-20251223195122-0076eee94506
 	github.com/tetratelabs/wazero v1.10.1
 	github.com/wasilibs/go-pgquery v0.0.0-20250409022910-10ac41983c07
 	github.com/xeipuuv/gojsonschema v1.2.0
@@ -34,6 +34,12 @@ require (
 require (
 	cel.dev/expr v0.24.0 // indirect
 	filippo.io/edwards25519 v1.1.0 // indirect
+	github.com/ClickHouse/ch-go v0.69.0 // indirect
+	github.com/andybalholm/brotli v1.2.0 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/go-faster/city v1.0.1 // indirect
+	github.com/go-faster/errors v0.7.1 // indirect
+	github.com/google/uuid v1.6.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
 	github.com/jackc/pgconn v1.14.3 // indirect
@@ -43,23 +49,31 @@ require (
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/pgtype v1.14.0 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/klauspost/compress v1.18.0 // indirect
 	github.com/ncruces/julianday v1.0.0 // indirect
+	github.com/paulmach/orb v0.12.0 // indirect
+	github.com/pierrec/lz4/v4 v4.1.22 // indirect
 	github.com/pingcap/errors v0.11.5-0.20240311024730-e056997136bb // indirect
 	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/segmentio/asm v1.2.1 // indirect
+	github.com/shopspring/decimal v1.4.0 // 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
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
+	go.opentelemetry.io/otel v1.39.0 // indirect
+	go.opentelemetry.io/otel/trace v1.39.0 // indirect
 	go.uber.org/atomic v1.11.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.27.0 // indirect
-	golang.org/x/crypto v0.45.0 // indirect
+	go.yaml.in/yaml/v3 v3.0.4 // indirect
+	golang.org/x/crypto v0.46.0 // indirect
 	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
-	golang.org/x/net v0.47.0 // indirect
-	golang.org/x/sys v0.38.0 // indirect
-	golang.org/x/text v0.31.0 // indirect
+	golang.org/x/net v0.48.0 // indirect
+	golang.org/x/sys v0.39.0 // indirect
+	golang.org/x/text v0.32.0 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20251022142026-3a174f9686a8 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20251022142026-3a174f9686a8 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect