using workspace variable value in visual query builder?

How can i use the values from workspace variable of matlab program in SQL queries of visual query builder (i.e SELECT * FROM tablename WHERE salary>workspacevariable's value) instead of static values like (WHERE salary>1000)?

[Tibor Meszaros]

productdesc = 'Painting Set';

sqlquery = ['SELECT * FROM productTable ' ...

'WHERE productDescription = ' '''' productdesc ''''];

results = fetch(conn,sqlquery)