Added 'mappedTo' to returnColumns for single column mapping

Author: justinkenel

parser.js

@@ -309,10 +309,20 @@ return {
           });
           let name;
           if(column.alias) name=column.alias.value;
-          else name=column.expression;
+          else name=this.toSql(column.expression);
+
+					let mappedTo;
+					if(column.expression.type == 'identifier') {
+						mappedTo = {column: column.expression.value};
+					} else if (column.expression.type == 'column') {
+						mappedTo = {column: column.expression.name, table: column.expression.table};
+					}
+
           returnColumns.push({
             name: name,
-            sourceColumns: sourceColumns
+						expression: column.expression,
+            sourceColumns: sourceColumns,
+						mappedTo
           });
         });
       }

test/test1.js

@@ -8,6 +8,25 @@ const tests = [
       operation: 'select',
     },
     toSql: '(select * from (`test`))'
+  },{
+    sql: 'select x from test',
+    toSql: '(select `x` from (`test`))',
+		expected: {
+			returnColumns: [{
+				expression: {
+					type: 'identifier',
+					value: 'x'
+				},
+				mappedTo: {
+					column: 'x'
+				},
+				name: '`x`',
+				sourceColumns: [{
+					type: 'identifier',
+					value: 'x'
+				}]
+			}]
+		}
   },{
     sql: [
 			'select * # comments!',