Insert NULL value using prepare()
문제
I have similars queries
/* Query */
global $wpdb;
$tablename = $wpdb->prefix . 'data';
$sql = $wpdb->prepare(
"
UPDATE $tablename
SET
`date` = %s,
WHERE
id= %d
",
$_POST['date'] == '' ? "NULL": $_POST['date'],
$_POST['id']
);
$wpdb->query($sql);
This will results in:
UPDATE `date` SET 'NULL' WHERE `id` = $_POST['id']
so prepare() is adding single quotes to NULL and the query sets the field to NULL string not NULL value. The only fix for me is to take the variable outside of the prepare() function like this:
/* Query */
global $wpdb;
$tablename = $wpdb->prefix . 'data';
/* Here I declare the variabile outside of the prepare() */
$date = $output['date'] == '' ? "NULL" : $_POST['date'];
$sql = $wpdb->prepare(
"
UPDATE $tablename
SET
`date` = $date,
WHERE
id = %d
",
$_POST['id']
);
$wpdb->query($sql);
해결책
the quick solution I found is to str_replace empty value.
/* Query */
global $wpdb;
$tablename = $wpdb->prefix . 'data';
$sql = $wpdb->prepare(
"
UPDATE $tablename
SET
`date` = %s,
WHERE
id= %d
",
$_POST['date'],
$_POST['id']
);
// SQL = UPDATE prefix_data SET `date` = '' WHERE id = 1
$sql = str_replace("''",'NULL', $sql);
// SQL = UPDATE prefix_data SET `date` = NULL WHERE id = 1
$wpdb->query($sql);
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