Disallow subtraction on unsigned columns:

When you use subtraction between integer values where one is of type
UNSIGNED, the result is unsigned unless the NO_UNSIGNED_SUBTRACTION SQL
mode is enabled. See Section 12.10, “Cast Functions and Operators”.

diff --git a/inc/db/lib-mysql3.php b/inc/db/lib-mysql3.php
index 24fb6e42c869ecb996f84d3904c7ec0d76591213..fd86300e36f564c9617c005197002a3a793df0bd 100644 (file)
--- a/inc/db/lib-mysql3.php
+++ b/inc/db/lib-mysql3.php
@@ -231,6 +231,9 @@ function sqlConnectToDatabase ($host, $login, $password, $file, $line) {
        `character_set_connection`='utf8',
        `character_set_database`='utf8',
        `character_set_server`='utf8'", $file . ':' . __FUNCTION__, $line . ':' . __LINE__);
+
+               // Disallow subtraction for unsigned columns
+               sqlQuery("SET `sql_mode`='NO_UNSIGNED_SUBTRACTION'", $file . ':' . __FUNCTION__, $line . ':' . __LINE__);
        } // END - if
 
        // Return the resource

diff --git a/inc/db/lib-mysqli.php b/inc/db/lib-mysqli.php
index 27798e9bb278d18d779545955df0261cf1261b95..9a1be873010ff6d78a9cef318bfa8739c8d03437 100644 (file)
--- a/inc/db/lib-mysqli.php
+++ b/inc/db/lib-mysqli.php
@@ -218,6 +218,9 @@ function sqlConnectToDatabase ($host, $login, $password, $file, $line) {
        `character_set_connection`='utf8',
        `character_set_database`='utf8',
        `character_set_server`='utf8'", $file . ':' . __FUNCTION__, $line . ':' . __LINE__);
+
+               // Disallow subtraction for unsigned columns
+               sqlQuery("SET `sql_mode`='NO_UNSIGNED_SUBTRACTION'", $file . ':' . __FUNCTION__, $line . ':' . __LINE__);
        } // END - if
 
        // Any errors encountered?