fix a crash

Author: Jille

internal/compiler/resolve.go

@@ -80,26 +80,28 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 			aliasMap[*rv.Alias.Aliasname] = fqn
 		}
 	}
-	for _, f := range qc.fromClauses {
-		catCols := make([]*catalog.Column, 0, len(f.Columns))
-		for _, col := range f.Columns {
-			catCols = append(catCols, &catalog.Column{
-				Name:       col.Name,
-				Type:       ast.TypeName{Name: col.DataType},
-				IsNotNull:  col.NotNull,
-				IsUnsigned: col.Unsigned,
-				IsArray:    col.IsArray,
-				ArrayDims:  col.ArrayDims,
-				Comment:    col.Comment,
-				Length:     col.Length,
-			})
-		}
+	if qc != nil {
+		for _, f := range qc.fromClauses {
+			catCols := make([]*catalog.Column, 0, len(f.Columns))
+			for _, col := range f.Columns {
+				catCols = append(catCols, &catalog.Column{
+					Name:       col.Name,
+					Type:       ast.TypeName{Name: col.DataType},
+					IsNotNull:  col.NotNull,
+					IsUnsigned: col.Unsigned,
+					IsArray:    col.IsArray,
+					ArrayDims:  col.ArrayDims,
+					Comment:    col.Comment,
+					Length:     col.Length,
+				})
+			}
 
-		if err := indexTable(catalog.Table{
-			Rel:     f.Rel,
-			Columns: catCols,
-		}); err != nil {
-			return nil, err
+			if err := indexTable(catalog.Table{
+				Rel:     f.Rel,
+				Columns: catCols,
+			}); err != nil {
+				return nil, err
+			}
 		}
 	}