SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 3) ExpressionList (children 1) Function format (children 1) ExpressionList (children 3) Literal \'Hello {1} World {0}\' Function materialize (children 1) ExpressionList (children 1) Literal \'first\' Function materialize (children 1) ExpressionList (children 1) Literal \'second\' TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier system.numbers Literal UInt64_1