diff --git a/lib/core/common.py b/lib/core/common.py
index 709569160..f0a97387a 100644
--- a/lib/core/common.py
+++ b/lib/core/common.py
@@ -2682,7 +2682,11 @@ def decodeIntToUnicode(value):
     Decodes inferenced integer value with usage of current page encoding
     """
     try:
-        return unichr(value)
+        # http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_ord
+        if Backend.getIdentifiedDbms() in (DBMS.MYSQL,):
+            return struct.pack('B' if value<256 else '<H', value).decode(kb.pageEncoding or UNICODE_ENCODING)
+        else:
+            return unichr(value)
     except:
         return INFERENCE_UNKNOWN_CHAR
 
diff --git a/xml/queries.xml b/xml/queries.xml
index 0f15034fa..960f4d9a6 100644
--- a/xml/queries.xml
+++ b/xml/queries.xml
@@ -224,9 +224,9 @@
         <count query="COUNT(%s)"/>
         <comment query="--"/>
         <timedelay query="BEGIN DBMS_LOCK.SLEEP(%d); END" query2="EXEC DBMS_LOCK.SLEEP(%d.00)" query3="EXEC USER_LOCK.SLEEP(%d.00)"/>
-        <substring query="SUBSTR((%s),%d,%d)"/>
+        <substring query="SUBSTRC((%s),%d,%d)"/>
         <case query="SELECT (CASE WHEN (%s) THEN 1 ELSE 0 END)"/>
-        <inference query="ASCII(SUBSTR((%s),%d,1)) > %d"/>
+        <inference query="ASCII(SUBSTRC((%s),%d,1)) > %d"/>
         <banner query="SELECT banner FROM v$version WHERE ROWNUM=1"/>
         <current_user query="SELECT USER FROM DUAL"/>
         <!--