Explain EXPLAIN (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 5)
    ExpressionList (children 1)
     Subquery (alias reference_vec) (children 1)
      SelectWithUnionQuery (children 1)
       ExpressionList (children 1)
        SelectQuery (children 1)
         ExpressionList (children 1)
          Literal Array_[Float64_0, Float64_2]
    ExpressionList (children 3)
     Identifier id
     Identifier vec
     Function cosineDistance (alias distance) (children 1)
      ExpressionList (children 2)
       Identifier vec
       Identifier reference_vec
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier tab
    ExpressionList (children 1)
     OrderByElement (children 1)
      Identifier distance
    Literal UInt64_1
