Select a portion from a MySQL Blob Field

Question

I have a table containing lots of data and one of them is a blob. I some times needs to look into this blob for data using PHP.

I do:

select `desc` f         


        

Answer 1

This query:

SELECT 
  CONCAT(
    '...', 
    SUBSTR(`description`, 
      LOCATE('Nam rhoncus', `description`) - 10, 
      (LENGTH('Nam rhoncus') + 20)), 
    '...') AS `description`
FROM table 
WHERE `description` LIKE '%Nam rhoncus%';

(I broke it down like this so it's easier to read)

this will output:

...m auctor. Nam rhoncus, purus eg...

So in your PHP you can do:

<?php
define('CHAR_LEFT', 10);
define('CHAR_RIGHT', 10);
// db stuff
$search = mysql_real_escape_string($search_var);
$query = "SELECT CONCAT('...', SUBSTR(`description`, LOCATE('" . $search . "', `description`) - " . CHAR_LEFT . ", (LENGTH('" . $search . "') + " . (CHAR_LEFT + CHAR_RIGHT) . ")), '...') AS `description` FROM table WHERE `description` LIKE '%" . $search . "%';";
// then your request

NOTE: Ill be careful using mysql reversed words, this is why I use description instead.

Answer 2

Something like the following should do what you need:

SELECT
    SUBSTR(description, INSTR(description, 'Nam rhoncus'), LENGTH('Nam rhoncus')) matchStr
FROM
    testTable
WHERE
    description like '%Nam rhoncus%'
;