diff --git a/trytond/model/modelsql.py b/trytond/model/modelsql.py
index 8fb2ffc5d9..1b78ae27f5 100644
--- a/trytond/model/modelsql.py
+++ b/trytond/model/modelsql.py
@@ -1485,42 +1485,39 @@ class ModelSQL(ModelStorage):
                         qu2.append(arg[2])
                     else:
                         add_null = False
-                        if arg[1] in ('like', 'ilike', 'not like', 'not ilike'):
-                            qu2.append('%% %s%%' % arg[2])
-                            qu2.append('%s%%' % arg[2])
+                        if arg[1] in ('like', 'ilike'):
                             if not arg[2]:
-                                add_null = True
+                                qu2.append('%')
+                                qu2.append('%')
+                                add_null = ' AND '
+                            else:
+                                qu2.append('%% %s%%' % arg[2])
+                                qu2.append('%s%%' % arg[2])
+                        elif arg[1] in ('not like', 'not ilike'):
+                            if not arg[2]:
+                                qu2.append('')
+                                qu2.append('')
+                            else:
+                                qu2.append('%% %s%%' % arg[2])
+                                qu2.append('%s%%' % arg[2])
+                                add_null = ' OR '
                         else:
                             if arg[0] in table._columns:
                                 qu2.append(FIELDS[table._columns[arg[0]]._type].\
                                         sql_format(arg[2]))
-                        if arg[0] in table._columns:
-                            if arg[1] in ('like', 'ilike'):
-                                qu1.append('("%s".%s %s %s OR "%s".%s %s %s)' % \
-                                        (table._table, arg[0], arg[1], '%s',
-                                            table._table, arg[0], arg[1], '%s'))
-                            elif arg[1] in ('not like', 'not ilike'):
-                                qu1.append('("%s".%s %s %s AND "%s".%s %s %s)' % \
-                                        (table._table, arg[0], arg[1], '%s',
-                                            table._table, arg[0], arg[1], '%s'))
-                            else:
-                                qu1.append('("%s".%s %s %%s)' % (table._table,
-                                    arg[0], arg[1]))
+                        if arg[1] in ('like', 'ilike'):
+                            qu1.append('("%s".%s %s %s OR "%s".%s %s %s)' % \
+                                    (table._table, arg[0], arg[1], '%s',
+                                        table._table, arg[0], arg[1], '%s'))
+                        elif arg[1] in ('not like', 'not ilike'):
+                            qu1.append('("%s".%s %s %s AND "%s".%s %s %s)' % \
+                                    (table._table, arg[0], arg[1], '%s',
+                                        table._table, arg[0], arg[1], '%s'))
                         else:
-                            if arg[1] in ('like', 'ilike'):
-                                qu1.append('("%s".%s %s \'%s\' or "%s".%s %s \'%s\')' % \
-                                        (table._table, arg[0], arg[1], arg[2],
-                                            table._table, arg[0], arg[1], arg[2]))
-                            elif arg[1] in ('not like', 'not ilike'):
-                                qu1.append('("%s".%s %s \'%s\' and "%s".%s %s \'%s\')' % \
-                                        (table._table, arg[0], arg[1], arg[2],
-                                            table._table, arg[0], arg[1], arg[2]))
-                            else:
-                                qu1.append('("%s".%s %s \'%s\')' % \
-                                        (table._table, arg[0], arg[1], arg[2]))
-
+                            qu1.append('("%s".%s %s %%s)' % (table._table,
+                                arg[0], arg[1]))
                         if add_null:
-                            qu1[-1] = '(' + qu1[-1] + ' OR ' + \
+                            qu1[-1] = '(' + qu1[-1] + add_null + \
                                     '"' + table._table + '".' + arg[0] +' IS NULL)'
 
         return qu1, qu2