SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 2)
    Identifier name
    Identifier type
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.data_skipping_indices
   Function and (children 1)
    ExpressionList (children 2)
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier table
       Literal \'tab\'
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier database
       Function currentDatabase (children 1)
        ExpressionList
   Literal UInt64_1