날짜 검색시 date_format() 쓰면 인덱스 안탐

$date_condition .= ($date_condition ? ' and ' : '') . "
(
	(A.cs_inflow_date BETWEEN '".$step_sdate." 00:00:00' AND '".$step_edate." 23:59:59')
	OR
	(A.cs_join_date BETWEEN '".$step_sdate." 00:00:00' AND '".$step_edate." 23:59:59')
	OR
	(A.cs_join_deposit_date BETWEEN '".$step_sdate." 00:00:00' AND '".$step_edate." 23:59:59')
)
";