multiple choice question, randomize once, two columns:

question:
Read the following statements and tick the box next to the correct answer below.

int a=10;
int b=20;

a=b;

The new values of a and b:

subquestion:
a=20 b=0

other:
any other values for a and b:

try preview question. Result is error

Error executing query in dbExecuteAssoc:CDbCommand failed to execute the SQL statement: SQLSTATE[42601]: Syntax error: 7 ERROR: non-integer constant in ORDER BY LINE 1: ...t_qid=5 AND scale_id=0 AND language='en' ORDER BY 0.98433262... ^. The SQL statement executed was: SELECT * FROM lime_questions WHERE parent_qid=5 AND scale_id=0 AND language='en' ORDER BY 0.98433262883484