Add a comment and a test case

h2/src/main/org/h2/expression/ExpressionColumn.java

@@ -216,6 +216,9 @@ public class ExpressionColumn extends Expression {
                 throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL());
             }
         }
+        /*
+         * ENUM values are stored as integers.
+         */
         if (value != ValueNull.INSTANCE) {
             ExtTypeInfo extTypeInfo = column.getType().getExtTypeInfo();
             if (extTypeInfo != null) {

h2/src/test/org/h2/test/scripts/datatypes/enum.sql

@@ -26,6 +26,11 @@ select * from card;
 > 4    null
 > rows: 3
 
+@reconnect
+
+select suit from card where rank = 0;
+>> clubs
+
 alter table card alter column suit enum('a', 'b', 'c', 'd');
 > exception ENUM_VALUE_NOT_PERMITTED