UNIQUE was not listed as a keyword.

h2/src/docsrc/html/advanced.html

@@ -403,7 +403,8 @@ unless they are quoted (surrounded with double quotes). The list is currently:
 <code>
 CROSS, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DISTINCT, EXCEPT, EXISTS, FALSE,
 FOR, FROM, FULL, GROUP, HAVING, INNER, INTERSECT, IS, JOIN, LIKE, LIMIT, MINUS, NATURAL, NOT, NULL,
-ON, ORDER, PRIMARY, ROWNUM, SELECT, SYSDATE, SYSTIME, SYSTIMESTAMP, TODAY, TRUE, UNION, WHERE
+ON, ORDER, PRIMARY, ROWNUM, SELECT, SYSDATE, SYSTIME, SYSTIMESTAMP, TODAY, TRUE, UNION, 
+UNIQUE, WHERE
 </code>
 </p><p>
 Certain words of this list are keywords because they are functions that can be used without '()' for compatibility,

h2/src/main/org/h2/jdbc/JdbcDatabaseMetaData.java

@@ -1347,7 +1347,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements DatabaseMetaDat
      * EXCEPT, EXISTS, FALSE, FOR, FROM, FULL, GROUP, HAVING, INNER,
      * INTERSECT, IS, JOIN, LIKE, LIMIT, MINUS, NATURAL, NOT, NULL, ON,
      * ORDER, PRIMARY, ROWNUM, SELECT, SYSDATE, SYSTIME, SYSTIMESTAMP,
-     * TODAY, TRUE, UNION, WHERE
+     * TODAY, TRUE, UNION, UNIQUE, WHERE
      * </pre>
      *
      * @return a list of additional the keywords