When I upgraded to 2.5 from 1.9 via 2.2 I found that the front page was showing this error where the course categories are listed :-

Default exception handler: Error reading from database Debug:
ERROR: syntax error at or near "hassummary" at character 116
SELECT c.id,c.category,c.sortorder,c.shortname,c.fullname,c.idnumber,c.startdate,c.visible,SUBSTR(c.summary, 1, 1) hassummary, ctx.id AS ctxid, ctx.path AS ctxpath, ctx.depth AS ctxdepth, ctx.contextlevel AS ctxlevel, ctx.instanceid AS ctxinstance
FROM mdl_course c
JOIN mdl_context ctx ON c.id = ctx.instanceid AND ctx.contextlevel = $1
WHERE c.id <> $2 AND c.category = $3 ORDER BY c.sortorder
[array (
0 => 50,
1 => '1',
2 => '11',
)]
Error code: dmlreadexception

• line 423 of /lib/dml/moodle_database.php: dml_read_exception thrown
• line 288 of /lib/dml/pgsql_native_moodle_database.php: call to moodle_database->query_end()
• line 800 of /lib/dml/pgsql_native_moodle_database.php: call to pgsql_native_moodle_database->query_end()
• line 843 of /lib/coursecatlib.php: call to pgsql_native_moodle_database->get_records_sql()
• line 1260 of /lib/coursecatlib.php: call to coursecat::get_course_records()
• line 1295 of /lib/coursecatlib.php: call to coursecat->get_courses()
• line 1452 of /course/renderer.php: call to coursecat->get_courses_count()
• line 1348 of /course/renderer.php: call to core_course_renderer->coursecat_category()
• line 1375 of /course/renderer.php: call to core_course_renderer->coursecat_subcategories()
• line 1477 of /course/renderer.php: call to core_course_renderer->coursecat_category_content()
• line 1933 of /course/renderer.php: call to core_course_renderer->coursecat_tree()
• line 254 of /index.php: call to core_course_renderer->frontpage_categories_list()
  , referer: http://localhost/admin/settings.php?section=debugging