diff --git a/src/calibre/gui2/library/models.py b/src/calibre/gui2/library/models.py
index 49cb1ce182..6a48aef9be 100644
--- a/src/calibre/gui2/library/models.py
+++ b/src/calibre/gui2/library/models.py
@@ -526,7 +526,7 @@ class BooksModel(QAbstractTableModel): # {{{
         def tags(r, idx=-1):
             tags = self.db.data[r][idx]
             if tags:
-                return QVariant(', '.join(sorted(tags.split(','), key=sort_key)))
+                return QVariant(', '.join(tags.split(',')))
             return None
 
         def series_type(r, idx=-1, siix=-1):
@@ -577,7 +577,7 @@ class BooksModel(QAbstractTableModel): # {{{
         def text_type(r, mult=False, idx=-1):
             text = self.db.data[r][idx]
             if text and mult:
-                return QVariant(', '.join(sorted(text.split('|'),key=sort_key)))
+                return QVariant(', '.join(text.split('|')))
             return QVariant(text)
 
         def number_type(r, idx=-1):
diff --git a/src/calibre/library/custom_columns.py b/src/calibre/library/custom_columns.py
index 07ea407460..558f3b8fc9 100644
--- a/src/calibre/library/custom_columns.py
+++ b/src/calibre/library/custom_columns.py
@@ -14,6 +14,7 @@ from calibre.constants import preferred_encoding
 from calibre.library.field_metadata import FieldMetadata
 from calibre.utils.date import parse_date
 from calibre.utils.config import tweaks
+from calibre.utils.icu import sort_key
 
 class CustomColumns(object):
 
@@ -181,8 +182,8 @@ class CustomColumns(object):
         ans = row[self.FIELD_MAP[data['num']]]
         if data['is_multiple'] and data['datatype'] == 'text':
             ans = ans.split('|') if ans else []
-            if data['display'].get('sort_alpha', False):
-                ans.sort(cmp=lambda x,y:cmp(x.lower(), y.lower()))
+            if data['display'].get('sort_alpha', True):
+                ans.sort(key=sort_key)
         return ans
 
     def get_custom_extra(self, idx, label=None, num=None, index_is_id=False):
@@ -534,8 +535,8 @@ class CustomColumns(object):
             if data['normalized']:
                 query = '%s.value'
                 if data['is_multiple']:
-                    query = 'group_concat(%s.value, "|")'
-                    if not display.get('sort_alpha', False):
+                    query = 'cc_sortconcat(%s.value)'
+                    if not display.get('sort_alpha', True):
                         query = 'sort_concat(link.id, %s.value)'
                 line = '''(SELECT {query} FROM {lt} AS link INNER JOIN
                     {table} ON(link.value={table}.id) WHERE link.book=books.id)
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 611aa1cc89..0b1c6a6cfb 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -242,7 +242,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
              'timestamp',
              '(SELECT MAX(uncompressed_size) FROM data WHERE book=books.id) size',
             ('rating', 'ratings', 'rating', 'ratings.rating'),
-            ('tags', 'tags', 'tag', 'group_concat(name)'),
+            ('tags', 'tags', 'tag', 'tags_sortconcat(name)'),
              '(SELECT text FROM comments WHERE book=books.id) comments',
             ('series', 'series', 'series', 'name'),
             ('publisher', 'publishers', 'publisher', 'name'),
diff --git a/src/calibre/library/sqlite.py b/src/calibre/library/sqlite.py
index 0458ada27b..0c3ae487ea 100644
--- a/src/calibre/library/sqlite.py
+++ b/src/calibre/library/sqlite.py
@@ -19,7 +19,7 @@ from calibre.ebooks.metadata import title_sort, author_to_author_sort
 from calibre.utils.date import parse_date, isoformat
 from calibre import isbytestring, force_unicode
 from calibre.constants import iswindows, DEBUG
-from calibre.utils.icu import strcmp
+from calibre.utils.icu import strcmp, sort_key
 
 global_lock = RLock()
 
@@ -69,6 +69,25 @@ class Concatenate(object):
             return None
         return self.sep.join(self.ans)
 
+class TagsSortConcatenate(object):
+    '''Sorted string concatenation aggregator for sqlite'''
+    def __init__(self, sep=','):
+        self.sep = sep
+        self.ans = []
+
+    def step(self, value):
+        if value is not None:
+            self.ans.append(value)
+
+    def finalize(self):
+        if not self.ans:
+            return None
+        return self.sep.join(sorted(self.ans, key=sort_key))
+
+class CcSortConcatenate(TagsSortConcatenate):
+    def __init__(self):
+        TagsSortConcatenate.__init__(self, sep='|')
+
 class SortedConcatenate(object):
     '''String concatenation aggregator for sqlite, sorted by supplied index'''
     sep = ','
@@ -155,6 +174,8 @@ class DBThread(Thread):
         c_ext_loaded = load_c_extensions(self.conn)
         self.conn.row_factory = sqlite.Row if self.row_factory else  lambda cursor, row : list(row)
         self.conn.create_aggregate('concat', 1, Concatenate)
+        self.conn.create_aggregate('tags_sortconcat', 1, TagsSortConcatenate)
+        self.conn.create_aggregate('cc_sortconcat', 1, CcSortConcatenate)
         if not c_ext_loaded:
             self.conn.create_aggregate('sortconcat', 2, SortedConcatenate)
             self.conn.create_aggregate('sort_concat', 2, SafeSortedConcatenate)