SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function count (children 1)
     ExpressionList
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier tab
   Function mapContains (children 1)
    ExpressionList (children 2)
     Identifier map_fixed
     Function toFixedString (children 1)
      ExpressionList (children 2)
       Literal \'K3\'
       Literal UInt64_2
