// rows in some manner. Requires all input rows to be processed,
// before a result is returned.
//
// Row function - An expression that depends on a value in the
// row. They have an output for each input row.
//
// Some types of a queries are not valid. For example, an aggregation
// function combined with a row function is meaningless ("AVG(s.Age) +
// s.Salary"). Analysis determines if such a scenario exists so an

		return &aggVal{runningMin: FromInt(0)}
	case aggFnMax:
		return &aggVal{runningMax: FromInt(0)}
	default:
		return &aggVal{}
	}
}

// evalAggregationNode - performs partial computation using the
// current row and stores the result.
//
// On success, it returns (nil, nil).
func (e *FuncExpr) evalAggregationNode(r Record, tableAlias string) error {
	// It is assumed that this function is called only when

func (e *SelectStatement) Eval(input, output Record) (Record, error) {
	ok, err := e.isPassingWhereClause(input)
	if err != nil || !ok {
		// Either error or row did not pass where clause
		return nil, err
	}

	if e.selectAST.Expression.All {
		// Return the input record for `SELECT * FROM
		// .. WHERE ..`

		// Update count of records output.
		e.outputCount++