@Override
public String toString() {
QueryModelTreePrinter treePrinter = new QueryModelTreePrinter();
SqlMbrContains clone = this.clone();
UnarySqlOperator parent = new UnarySqlOperator(clone){
@Override
public <X extends Exception> void visit(
RdbmsQueryModelVisitorBase<X> visitor) throws X {
visitor.meetOther(this);
}};
new SqlConstantOptimizer().optimize(clone);
parent.getArg().visit(treePrinter);
return treePrinter.getTreeString();
}