diff --git a/driver/defs.h b/driver/defs.h
index ecf3d19a..121133d4 100644
--- a/driver/defs.h
+++ b/driver/defs.h
@@ -284,8 +284,9 @@
  * Timedate functions support:
  * - supported: DAYNAME, DAYOFMONTH, DAYOFWEEK, DAYOFYEAR, EXTRACT, HOUR,
  *   MINUTE, MONTH, MONTHNAME, QUARTER, SECOND, WEEK, YEAR, NOW,
- *   CURRENT_TIMESTAMP, CURRENT_DATE, CURDATE, CURRENT_TIME, CURTIME;
- * - not supported: TIMESTAMPADD, TIMESTAMPDIFF.
+ *   CURRENT_TIMESTAMP, CURRENT_DATE, CURDATE, CURRENT_TIME, CURTIME,
+ *   TIMESTAMPADD, TIMESTAMPDIFF;
+ * - not supported: none.
  */
 #define ESODBC_TIMEDATE_FUNCTIONS				(0LU | \
 	SQL_FN_TD_DAYNAME | SQL_FN_TD_DAYOFMONTH | SQL_FN_TD_DAYOFWEEK | \
@@ -294,22 +295,28 @@
 	SQL_FN_TD_QUARTER | SQL_FN_TD_SECOND | SQL_FN_TD_WEEK | \
 	SQL_FN_TD_YEAR | SQL_FN_TD_NOW | SQL_FN_TD_CURRENT_TIMESTAMP | \
 	SQL_FN_TD_CURDATE | SQL_FN_TD_CURRENT_DATE | SQL_FN_TD_CURRENT_TIME | \
-	SQL_FN_TD_CURTIME)
+	SQL_FN_TD_CURTIME | SQL_FN_TD_TIMESTAMPADD | SQL_FN_TD_TIMESTAMPDIFF)
 
 /*
  * TIMESTAMPDIFF timestamp intervals:
- * - supported: none.
- * - not supported: FRAC_SECOND, SECOND, MINUTE, HOUR, DAY, WEEK, MONTH,
- *   QUARTER, YEAR.
+ * - supported: FRAC_SECOND, SECOND, MINUTE, HOUR, DAY, WEEK, MONTH,
+ *   QUARTER, YEAR;
+ * - not supported: none.
  */
-#define ESODBC_TIMEDATE_DIFF_INTERVALS			0LU
+#define ESODBC_TIMEDATE_DIFF_INTERVALS			(0LU | \
+	SQL_FN_TSI_DAY | SQL_FN_TSI_FRAC_SECOND | SQL_FN_TSI_HOUR | \
+	SQL_FN_TSI_MINUTE | SQL_FN_TSI_MONTH | SQL_FN_TSI_QUARTER | \
+	SQL_FN_TSI_SECOND | SQL_FN_TSI_WEEK | SQL_FN_TSI_YEAR)
 /*
  * TIMESTAMPADD timestamp intervals:
- * - supported: none
- * - not supported: FRAC_SECOND, SECOND, MINUTE, HOUR, DAY, WEEK, MONTH,
- *   QUARTER, YEAR.
+ * - supported: FRAC_SECOND, SECOND, MINUTE, HOUR, DAY, WEEK, MONTH,
+ *   QUARTER, YEAR;
+ * - not supported: none.
  */
-#define ESODBC_TIMEDATE_ADD_INTERVALS			0LU
+#define ESODBC_TIMEDATE_ADD_INTERVALS			(0LU | \
+	SQL_FN_TSI_DAY | SQL_FN_TSI_FRAC_SECOND | SQL_FN_TSI_HOUR | \
+	SQL_FN_TSI_MINUTE | SQL_FN_TSI_MONTH | SQL_FN_TSI_QUARTER | \
+	SQL_FN_TSI_SECOND | SQL_FN_TSI_WEEK | SQL_FN_TSI_YEAR)
 /*
  * System functions:
  * - supported: DATABASE, IFNULL, USER.