게시판 검색을 만들었는데 작동이 안되네요.

<!-- 게시판 검색 시작 { -->
<?php
$val_from = trim($val_from);
if ($sfl==wr_5){
    $val_from = wr_5;
    $val_to = wr_5;
} else {
    $val_from = wr_6;
    $val_to = wr_6;}
if ($sfl=$val_from){
    $sql_search = " {$sfl} between '{$val_from}' and '{$val_to}' ";}
?>

<fieldset id="bo_sch">
    <legend>분양가 검색</legend>

    <form name="fsearch" method="get">
    <input type="hidden" name="bo_table" value="<?php echo $bo_table ?>">
    <input type="hidden" name="sca" value="<?php echo $sca ?>">
    <input type="hidden" name="sop" value="and">
    <label for="sfl" class="sound_only">검색대상</label>
    <select name="sfl" id="sfl">
        <option value="wr_5"<?php echo get_selected($sfl, 'wr_5'); ?>>분양가</option>
        <option value="wr_6"<?php echo get_selected($sfl, 'wr_6'); ?>>융자금</option>
    </select>
    <label class="sound_only">검색어<strong class="sound_only"> 필수</strong></label>
    <input type="text" name="val_from" value="<?php echo stripslashes($val_from) ?>" required id="val_from" class="frm_input required" size="15" maxlength="20">~
    <input type="text" name="val_to" value="<?php echo stripslashes($val_to) ?>" required id="val_to" class="frm_input required" size="15" maxlength="20">
    <input type="submit" value="검색" class="btn_submit">
    </form>
</fieldset>
<!-- } 게시판 검색 끝 -->