diff --git a/internal/compiler/output_columns.go b/internal/compiler/output_columns.go
index e81348a596..19deb8bddc 100644
--- a/internal/compiler/output_columns.go
+++ b/internal/compiler/output_columns.go
@@ -64,6 +64,20 @@ func outputColumns(qc *QueryCatalog, node ast.Node) ([]*Column, error) {
 		targets = n.ReturningList
 	case *ast.SelectStmt:
 		targets = n.TargetList
+
+		if n.GroupClause != nil {
+			for _, item := range n.GroupClause.Items {
+				ref, ok := item.(*ast.ColumnRef)
+				if !ok {
+					continue
+				}
+
+				if err := findColumnForRef(ref, tables); err != nil {
+					return nil, err
+				}
+			}
+		}
+
 		// For UNION queries, targets is empty and we need to look for the
 		// columns in Largs.
 		if len(targets.Items) == 0 && n.Larg != nil {
@@ -470,3 +484,43 @@ func outputColumnRefs(res *ast.ResTarget, tables []*Table, node *ast.ColumnRef)
 	}
 	return cols, nil
 }
+
+func findColumnForRef(ref *ast.ColumnRef, tables []*Table) error {
+	parts := stringSlice(ref.Fields)
+	var alias, name string
+	if len(parts) == 1 {
+		name = parts[0]
+	} else if len(parts) == 2 {
+		alias = parts[0]
+		name = parts[1]
+	}
+
+	var found int
+	for _, t := range tables {
+		if alias != "" && t.Rel.Name != alias {
+			continue
+		}
+		for _, c := range t.Columns {
+			if c.Name == name {
+				found++
+			}
+		}
+	}
+
+	if found == 0 {
+		return &sqlerr.Error{
+			Code:     "42703",
+			Message:  fmt.Sprintf("column reference \"%s\" not found", name),
+			Location: ref.Location,
+		}
+	}
+	if found > 1 {
+		return &sqlerr.Error{
+			Code:     "42703",
+			Message:  fmt.Sprintf("column reference \"%s\" is ambiguous", name),
+			Location: ref.Location,
+		}
+	}
+
+	return nil
+}
diff --git a/internal/endtoend/testdata/invalid_group_by_reference/mysql/query.sql b/internal/endtoend/testdata/invalid_group_by_reference/mysql/query.sql
new file mode 100644
index 0000000000..75a8e210fd
--- /dev/null
+++ b/internal/endtoend/testdata/invalid_group_by_reference/mysql/query.sql
@@ -0,0 +1,11 @@
+CREATE TABLE authors (
+  id   BIGINT  NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  name text    NOT NULL,
+  bio  text,
+  UNIQUE(name)
+);
+
+-- name: ListAuthors :many
+SELECT   *
+FROM     authors
+GROUP BY invalid_reference;
diff --git a/internal/endtoend/testdata/invalid_group_by_reference/mysql/sqlc.json b/internal/endtoend/testdata/invalid_group_by_reference/mysql/sqlc.json
new file mode 100644
index 0000000000..534b7e24e9
--- /dev/null
+++ b/internal/endtoend/testdata/invalid_group_by_reference/mysql/sqlc.json
@@ -0,0 +1,12 @@
+{
+	"version": "1",
+	"packages": [
+		{
+			"path": "go",
+			"engine": "mysql",
+			"name": "querytest",
+			"schema": "query.sql",
+			"queries": "query.sql"
+		}
+	]
+}
diff --git a/internal/endtoend/testdata/invalid_group_by_reference/mysql/stderr.txt b/internal/endtoend/testdata/invalid_group_by_reference/mysql/stderr.txt
new file mode 100644
index 0000000000..18a7d6bd0f
--- /dev/null
+++ b/internal/endtoend/testdata/invalid_group_by_reference/mysql/stderr.txt
@@ -0,0 +1,2 @@
+# package querytest
+query.sql:9:1: column reference "invalid_reference" not found
diff --git a/internal/endtoend/testdata/invalid_group_by_reference/postgresql/query.sql b/internal/endtoend/testdata/invalid_group_by_reference/postgresql/query.sql
new file mode 100644
index 0000000000..fdfa7e4e05
--- /dev/null
+++ b/internal/endtoend/testdata/invalid_group_by_reference/postgresql/query.sql
@@ -0,0 +1,10 @@
+CREATE TABLE authors (
+  id   BIGSERIAL PRIMARY KEY,
+  name text      NOT NULL,
+  bio  text
+);
+
+-- name: ListAuthors :many
+SELECT   *
+FROM     authors
+GROUP BY invalid_reference;
diff --git a/internal/endtoend/testdata/invalid_group_by_reference/postgresql/sqlc.json b/internal/endtoend/testdata/invalid_group_by_reference/postgresql/sqlc.json
new file mode 100644
index 0000000000..af57681f66
--- /dev/null
+++ b/internal/endtoend/testdata/invalid_group_by_reference/postgresql/sqlc.json
@@ -0,0 +1,12 @@
+{
+	"version": "1",
+	"packages": [
+		{
+			"path": "go",
+			"engine": "postgresql",
+			"name": "querytest",
+			"schema": "query.sql",
+			"queries": "query.sql"
+		}
+	]
+}
diff --git a/internal/endtoend/testdata/invalid_group_by_reference/postgresql/stderr.txt b/internal/endtoend/testdata/invalid_group_by_reference/postgresql/stderr.txt
new file mode 100644
index 0000000000..e9dd12bc6f
--- /dev/null
+++ b/internal/endtoend/testdata/invalid_group_by_reference/postgresql/stderr.txt
@@ -0,0 +1,2 @@
+# package querytest
+query.sql:10:10: column reference "invalid_reference" not found
diff --git a/internal/engine/dolphin/convert.go b/internal/engine/dolphin/convert.go
index 8e1247c048..053b1f549c 100644
--- a/internal/engine/dolphin/convert.go
+++ b/internal/engine/dolphin/convert.go
@@ -474,6 +474,7 @@ func (c *cc) convertSelectStmt(n *pcast.SelectStmt) *ast.SelectStmt {
 	stmt := &ast.SelectStmt{
 		TargetList:   c.convertFieldList(n.Fields),
 		FromClause:   c.convertTableRefsClause(n.From),
+		GroupClause:  c.convertGroupByClause(n.GroupBy),
 		WhereClause:  c.convert(n.Where),
 		WithClause:   c.convertWithClause(n.With),
 		WindowClause: windowClause,
@@ -677,7 +678,14 @@ func (c *cc) convertBinlogStmt(n *pcast.BinlogStmt) ast.Node {
 }
 
 func (c *cc) convertByItem(n *pcast.ByItem) ast.Node {
-	return todo(n)
+	switch n.Expr.(type) {
+	case *pcast.PositionExpr:
+		return c.convertPositionExpr(n.Expr.(*pcast.PositionExpr))
+	case *pcast.ColumnNameExpr:
+		return c.convertColumnNameExpr(n.Expr.(*pcast.ColumnNameExpr))
+	default:
+		return todo(n)
+	}
 }
 
 func (c *cc) convertCaseExpr(n *pcast.CaseExpr) ast.Node {
@@ -858,8 +866,19 @@ func (c *cc) convertGrantStmt(n *pcast.GrantStmt) ast.Node {
 	return todo(n)
 }
 
-func (c *cc) convertGroupByClause(n *pcast.GroupByClause) ast.Node {
-	return todo(n)
+func (c *cc) convertGroupByClause(n *pcast.GroupByClause) *ast.List {
+	if n == nil {
+		return &ast.List{}
+	}
+
+	var items []ast.Node
+	for _, item := range n.Items {
+		items = append(items, c.convertByItem(item))
+	}
+
+	return &ast.List{
+		Items: items,
+	}
 }
 
 func (c *cc) convertHavingClause(n *pcast.HavingClause) ast.Node {