SelectWithUnionQuery (children 2)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 7)
    Identifier name
    Identifier partition_key
    Identifier sorting_key
    Identifier primary_key
    Identifier sampling_key
    Identifier storage_policy
    Identifier total_rows
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.tables
   Function and (children 1)
    ExpressionList (children 2)
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier name
       Literal \'check_system_tables\'
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier database
       Function currentDatabase (children 1)
        ExpressionList
 Identifier PrettyCompactNoEscapes
