Disable a Drupal 7 theme in MySQL DB

disable_theme.sql

# Update theme variables
UPDATE variable SET value='s:7:"garland"' WHERE name = 'theme_default';
UPDATE system SET status=1 WHERE name = 'garland';
UPDATE system SET status=0 WHERE name = 'other_theme';

# Truncate cache tables
TRUNCATE cache;
TRUNCATE cache_bootstrap;
TRUNCATE cache_block;

# In settings.php
# $conf['theme_default'] = 'garland';