Explain EXPLAIN ESTIMATE (children 1) SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 3) ExpressionList (children 1) Function count (children 1) ExpressionList TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier test.hits Function notEquals (children 1) ExpressionList (children 2) Identifier CounterID Literal UInt64_29103473