Hi @dilipkumar,
I think I understand the problem you're facing now. It looks like the issue might be that the database is parsing the commas in your query string in a way you don't want, not that JMP is. SQL isn't my specialty, but I did a little searching and came across this post that discussed escaping characters, like commas, in SQL statements. The suggestion is to add double quotes to help identify the separate clauses since the comma alone isn't definitive if you're using commas elsewhere. In your example, that could look like the following when defining your MN variable, though I must say I don't have a way to test whether this will work so I offer it only as a possible suggestion:
MN = " \!"3C22\!",\!"Y MERS,.AAA-.75YIN\!" ";
// which stores the string, including quotes:
// "3C22" , "Y MERS,.AAA-.75YIN"
@julian