The wrong exception was thrown when using unquoted text for COMMENT, ALTER USER, and SET PASSWORD.

h2/src/main/org/h2/command/ddl/AlterUser.java

@@ -81,11 +81,11 @@ public class AlterUser extends DefineCommand {
     }
 
     private char[] getCharArray(Expression e) throws SQLException {
-        return e.getValue(session).getString().toCharArray();
+        return e.optimize(session).getValue(session).getString().toCharArray();
     }
 
     private byte[] getByteArray(Expression e) throws SQLException {
-        return ByteUtils.convertStringToBytes(e.getValue(session).getString());
+        return ByteUtils.convertStringToBytes(e.optimize(session).getValue(session).getString());
     }
 
     public int update() throws SQLException {

h2/src/main/org/h2/command/ddl/CreateUser.java

@@ -52,7 +52,7 @@ public class CreateUser extends DefineCommand {
     }
 
     private byte[] getByteArray(Expression e) throws SQLException {
-        return ByteUtils.convertStringToBytes(e.getValue(session).getString());
+        return ByteUtils.convertStringToBytes(e.optimize(session).getValue(session).getString());
     }
 
     public int update() throws SQLException {

h2/src/main/org/h2/command/ddl/SetComment.java

@@ -91,7 +91,7 @@ public class SetComment extends DefineCommand {
         if (object == null) {
             throw Message.getSQLException(errorCode, objectName);
         }
-        String text = expr.getValue(session).getString();
+        String text = expr.optimize(session).getValue(session).getString();
         if (column) {
             Table table = (Table) object;
             table.getColumn(columnName).setComment(text);

h2/src/test/org/h2/test/test-1.1.txt

@@ -2,6 +2,15 @@
 create table test(id identity);
 > ok
 
+set password test;
+> exception
+
+alter user sa set password test;
+> exception
+
+comment on table test is test;
+> exception
+
 select 1 from test a where 1 in(select 1 from test b where b.id in(select 1 from test c where c.id=a.id));
 > 1
 > -