Explain EXPLAIN SYNTAX (children 1) SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 3) ExpressionList (children 1) Asterisk TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) Subquery (children 1) SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 2) ExpressionList (children 1) Asterisk TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier system.one Function equals (children 1) ExpressionList (children 2) Function arrayMap (children 1) ExpressionList (children 2) Function lambda (children 1) ExpressionList (children 2) Function tuple (children 1) ExpressionList (children 1) Identifier x Function plus (children 1) ExpressionList (children 2) Identifier x Literal UInt64_1 Function array (children 1) ExpressionList (children 1) Identifier dummy Literal Array_[UInt64_1]