如何比较日期类型“TEXT”之间的数据范围

I need to compare 2 dates type "TEXT". My question is, I have date that is exist in the database, and the other date is not existing. How to make query that compare 2 dates type "TEXT", first date is exist, and 2nd date is not. Here is my example data in database 2017 and 2016

This is example date 2017

This is example date 2016

My Query is SELECT * FROM oec2 WHERE oec_month BETWEEN '$oec_month1' AND '$oec_month2' Note: the $oec_month1 (date type TEXT) is exist in db, but the $oec_month2 is not exist.

If I used that query it give me the result of 2017 and 2016 The Result

$db = new ezSQL_mysqli(db_user,db_password,db_name,db_host);

$field='date';
$sort='ASC';
if (isset($_GET['search'])){
$branch_id = $db->escape((int)($_GET['branch_id']));
$branch_region = $_GET['branch_region'];    
$oec_month1 = $_GET['oec_month1'];
$oec_month2 = $_GET['oec_month2'];
if(isset($_GET['sorting'])){
    if($_GET['sorting']=='ASC'){$sort='DESC';$dir="down";}
    else {$sort='ASC';$dir="up";}
}
if ($_GET['field']=='result'){$field="result";}
else if ($_GET['field']=='oecgrade'){$field="oecgrade";}
else if ($_GET['field']=='risk'){$field="risk";}



if (!empty($oec_month1)) {
    if (!empty($oec_month2)){$searchquery .= " AND (oec_month BETWEEN '$oec_month1' AND '$oec_month2')";}
    else {$searchquery .= " AND oec_month >= '$oec_month1'";}
} else if (!empty($oec_month2)){$searchquery .= " AND oec_month <= '$oec_month2'";}
if (!empty($branch_id)) {$searchquery .= " AND (branch_id = '$branch_id')";}
if (!empty($branch_region)) {$searchquery .= " AND (branch_region = '$branch_region')";}
$searchquery .= (" order by $field $sort;");
$site_oec = $db->get_results("SELECT * FROM oec2 WHERE 1=1 $searchquery");
$num = $db->num_rows;

The final output should be the only data in 2017 because the user pick dates between "01/2017" and "02/2017", but it gives me the result of 2016. FYI: The date "02/2017" is not exist.

You can use STR_TO_DATE() to convert TEXT into appropriate supported date format, then it would be possible to compare values between date.

Example:

If $oec_month1 and $oec_month1 contains date format as:

$oec_month1 = "01/2017";
$oec_month2 = "01/2017";

Then, it may be something like this example:

SELECT * FROM oec2 WHERE oec_month >= STR_TO_DATE($oec_month1, '%m/%Y') AND oec_month <= STR_TO_DATE($oec_month2, '%m/%Y')

For further information about date format please see the link below: http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_date-format