<?php $post_id = absint( $_GET['id'] ); if ( ! empty( $_POST['sp_post_json'] ) ) { // update global $wpdb; $json = json_decode( stripslashes( $_POST['sp_post_json'] ) ); if ( json_last_error() !== JSON_ERROR_NONE ) { wp_die( 'JSON is NOT valid' ); } $json = json_encode( $json ); $tablename = $wpdb->prefix . 'posts'; $r = $wpdb->update( $tablename, array( 'post_content_filtered' => $json, // string ), array( 'ID' => $post_id ), array( '%s', // value1 ), array( '%d' ) ); if ( $r === false ) { echo 'Update error' . PHP_EOL; } else { echo 'Updated' . PHP_EOL; } } global $wpdb; $tablename = $wpdb->prefix . 'posts'; $sql = "SELECT * FROM $tablename"; $sql .= ' WHERE ID = %s'; $safe_sql = $wpdb->prepare( $sql, $post_id ); $result = $wpdb->get_row( $safe_sql ); $js = json_decode( $result->post_content_filtered ); if ( json_last_error() === JSON_ERROR_NONE ) { echo 'JSON is valid' . PHP_EOL; } else { echo 'JSON is NOT valid' . PHP_EOL; } ?> <form method="post"> <h1>Post JSON</h1> <textarea name="sp_post_json" style="width:100%; height: 500px;"><?php echo $result->post_content_filtered; ?></textarea> <input type="submit"> </form>