fix(compiler): Add validation for GROUP BY clause column references

Author: timstudd

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 +484,44 @@ 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++
+				continue
+			}
+		}
+	}
+
+	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
+}

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;

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"
+		}
+	]
+}

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