How to get values of delta field from "block" table in drupal 7 from the database for the activated theme in a custom module?
SELECT delta, 
FROM  `module__block` 
WHERE theme LIKE  'business'
LIMIT 0 , 30 ;


shows only blocks.

SELECT delta, theme
FROM  module__block 
WHERE theme LIKE  'business'
LIMIT 0 , 30;

It will shows both the block names and theme name.