Get and Set Hook Update N Schema Version Number

How to find a Drupal 7 module's [=hook_update_N()=] schema version number.

Print Module Information with Drush

drush pmi my_module

Example

$ drush @local pmi php
 Extension        :  php                                                
 Project          :  drupal                                             
 Type             :  module                                             
 Title            :  PHP filter                                         
 Description      :  Allows embedded PHP code/snippets to be evaluated. 
 Version          :  7.26                                               
 Date             :  2014-01-15                                         
 Package          :  Core                                               
 Core             :  7.x                                                
 PHP              :  5.2.4                                              
 Status           :  enabled                                            
 Path             :  modules/php                                        
 Schema version   :  module has no schema                               
 Files            :  php.test                                           
 Requires         :  none                                               
 Required by      :  none                                               
 Permissions      :  use PHP for settings                               
 Configure        :  None   

MySQL

select name,schema_version from system where name = 'my_module';

Example

mysql> SELECT name,schema_version FROM system WHERE name = 'my_module';
+-----------+----------------+
| name      | schema_version |
+-----------+----------------+
| my_module |           7026 |
+-----------+----------------+

Query via Drush

drush sqlq "select name,schema_version from system where name = 'my_module'"

Reset a Schema Version to 0

; Do it with SQL...
UPDATE system SET schema_version = 0 WHERE name = 'my_module' LIMIT 1;

# Or do it with drush...
drush ss my_module 0

You can rollback the schema_version to whatever number is meaningful in your usecase. Setting to 0 will cause all up hook_update_N() methods to execute on next updb.