feat(parser): ClickHouse CODEC(...) column option (#482)

Author: Ajit Pratap Singh

pkg/sql/parser/clickhouse_codec_test.go

@@ -0,0 +1,40 @@
+// Copyright 2026 GoSQLX Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+
+package parser_test
+
+import (
+	"testing"
+
+	"github.com/ajitpratap0/GoSQLX/pkg/gosqlx"
+	"github.com/ajitpratap0/GoSQLX/pkg/sql/keywords"
+)
+
+// TestClickHouseCODEC verifies the ClickHouse CODEC(...) column option
+// parses in CREATE TABLE. Regression for #482.
+func TestClickHouseCODEC(t *testing.T) {
+	queries := map[string]string{
+		"single_codec": `CREATE TABLE t (
+			id UInt64,
+			payload String CODEC(ZSTD(3))
+		) ENGINE = MergeTree() ORDER BY id`,
+
+		"chained_codec": `CREATE TABLE t (
+			id UInt64,
+			ts DateTime CODEC(Delta, LZ4)
+		) ENGINE = MergeTree() ORDER BY id`,
+
+		"delta_with_width": `CREATE TABLE t (
+			id UInt64 CODEC(Delta(8), ZSTD)
+		) ENGINE = MergeTree() ORDER BY id`,
+	}
+	for name, q := range queries {
+		q := q
+		t.Run(name, func(t *testing.T) {
+			if _, err := gosqlx.ParseWithDialect(q, keywords.DialectClickHouse); err != nil {
+				t.Fatalf("parse failed: %v", err)
+			}
+		})
+	}
+}

pkg/sql/parser/ddl_columns.go

@@ -23,6 +23,7 @@ import (
 	goerrors "github.com/ajitpratap0/GoSQLX/pkg/errors"
 	"github.com/ajitpratap0/GoSQLX/pkg/models"
 	"github.com/ajitpratap0/GoSQLX/pkg/sql/ast"
+	"github.com/ajitpratap0/GoSQLX/pkg/sql/keywords"
 )
 
 // parseColumnName parses a column name in DDL context, accepting reserved keywords
@@ -92,6 +93,27 @@ func (p *Parser) parseColumnDef() (*ast.ColumnDef, error) {
 		Type: dataTypeStr,
 	}
 
+	// ClickHouse column options that may appear between the type and the
+	// standard constraint list: CODEC(...), DEFAULT expr, MATERIALIZED expr,
+	// ALIAS expr, EPHEMERAL expr, TTL expr. Consume permissively; they are
+	// appended to the type string for now so formatters can round-trip, and
+	// not yet modeled on the AST.
+	if p.dialect == string(keywords.DialectClickHouse) {
+		for {
+			upper := strings.ToUpper(p.currentToken.Token.Value)
+			if upper == "CODEC" && p.peekToken().Token.Type == models.TokenTypeLParen {
+				p.advance() // CODEC
+				args, err := p.parseTypeArgsString()
+				if err != nil {
+					return nil, err
+				}
+				colDef.Type += " CODEC" + args
+				continue
+			}
+			break
+		}
+	}
+
 	// Parse column constraints
 	for {
 		constraint, ok, err := p.parseColumnConstraint()