diff --git a/bin/pt-table-checksum b/bin/pt-table-checksum
index 3adee83e..344187be 100755
--- a/bin/pt-table-checksum
+++ b/bin/pt-table-checksum
@@ -9131,6 +9131,26 @@ sub main {
       return if $o->get('explain');
       my $sql;
 
+      # https://bugs.launchpad.net/percona-toolkit/+bug/1019479
+      # sql_mode ONLY_FULL_GROUP_BY often raises error even when query is
+      # safe and deterministic. It's best to turn it off for the session
+      # at this point.
+      $sql = 'SELECT @@SQL_MODE';
+      PTDEBUG && _d($dbh, $sql);
+      my ($sql_mode) = eval { $dbh->selectrow_array($sql) };
+      if ( $EVAL_ERROR ) {
+         die "Error getting the current SQL_MODE: $EVAL_ERROR";
+      }
+      $sql_mode =~ s/ONLY_FULL_GROUP_BY//i;
+      $sql = qq[SET SQL_MODE='$sql_mode'];
+      PTDEBUG && _d($dbh, $sql);
+      eval { $dbh->do($sql) };
+      if ( $EVAL_ERROR ) {
+         die "Error setting SQL_MODE"
+           . ": $EVAL_ERROR";
+      }
+ 
+
       # https://bugs.launchpad.net/percona-toolkit/+bug/919352
       # The tool shouldn't blindly attempt to change binlog_format;
       # instead, it should check if it's already set to STATEMENT.
diff --git a/t/pt-table-checksum/basics.t b/t/pt-table-checksum/basics.t
index 056fbd1b..de2eb369 100644
--- a/t/pt-table-checksum/basics.t
+++ b/t/pt-table-checksum/basics.t
@@ -56,6 +56,7 @@ sub reset_repl_db {
    $master_dbh->do("use $repl_db");
 }
 
+
 # ############################################################################
 # Default checksum and results.  The tool does not technically require any
 # options on well-configured systems (which the test env cannot be).  With
@@ -508,6 +509,24 @@ is(
    "Bug 821675 (dot): 0 errors"
 );
 
+# #############################################################################
+# Bug 1019479: does not work with sql_mode ONLY_FULL_GROUP_BY
+# #############################################################################
+
+# add a couple more modes to test that commas don't affect setting
+$master_dbh->do("SET sql_mode = 'NO_ZERO_DATE,ONLY_FULL_GROUP_BY,STRICT_ALL_TABLES'");
+
+# force chunk-size because bug doesn't show up if table done in one chunk 
+$exit_status = pt_table_checksum::main(@args,
+   qw(--quiet --quiet -t sakila.actor --chunk-size=50));
+
+is(
+   $exit_status,
+   0,
+   "sql_mode ONLY_FULL_GROUP_BY is overidden"
+);
+
+
 # #############################################################################
 # Done.
 # #############################################################################