Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)
    ExpressionList (children 1)
     Function replaceRegexpAll (children 1)
      ExpressionList (children 3)
       Function identity (children 1)
        ExpressionList (children 1)
         Literal \'abc123$\'
       Literal \'123\\\\$\'
       Literal \'\'
