ON clause in MERGE USING statement should not require ()

h2/src/docsrc/help/help.csv

@@ -122,7 +122,7 @@ MERGE INTO TEST KEY(ID) VALUES(2, 'World')
 "Commands (DML)","MERGE USING","
 MERGE INTO targetTableName [ [AS] targetAlias]
 USING { ( select ) | sourceTableName }[ [AS] sourceAlias ]
-ON ( expression )
+ON expression
 [ WHEN MATCHED THEN
     [ UPDATE SET setClauseList ] [ DELETE deleteSearchCondition ] ]
 [ WHEN NOT MATCHED THEN INSERT insertColumnsAndSource ]
@@ -138,20 +138,20 @@ If WHEN MATCHED THEN is specified it should contain UPDATE or DELETE clauses of
 If statement doesn't need a source table a DUAL table can be substituted.
 ","
 MERGE INTO TARGET_TABLE AS T USING SOURCE_TABLE AS S
-    ON (T.ID = S.ID)
+    ON T.ID = S.ID
     WHEN MATCHED THEN
         UPDATE SET T.COL1 = S.COL1 WHERE T.COL2<>'FINAL'
         DELETE WHERE T.COL2='FINAL'
     WHEN NOT MATCHED THEN
         INSERT (ID,COL1,COL2) VALUES(S.ID,S.COL1,S.COL2)
 MERGE INTO TARGET_TABLE AS T USING (SELECT * FROM SOURCE_TABLE) AS S
-    ON (T.ID = S.ID)
+    ON T.ID = S.ID
     WHEN MATCHED THEN
         UPDATE SET T.COL1 = S.COL1 WHERE T.COL2<>'FINAL'
         DELETE WHERE T.COL2='FINAL'
     WHEN NOT MATCHED THEN
         INSERT (ID,COL1,COL2) VALUES(S.ID,S.COL1,S.COL2)
-MERGE INTO TARGET_TABLE USING DUAL ON (ID = 1)
+MERGE INTO TARGET_TABLE USING DUAL ON ID = 1
     WHEN NOT MATCHED THEN INSERT (ID, NAME) VALUES (1, 'Test')
     WHEN MATCHED THEN UPDATE SET NAME = 'Test'
 "

h2/src/main/org/h2/command/Parser.java

@@ -1170,10 +1170,8 @@ public class Parser {
             command.setQuery(preparedQuery);
         }
         read("ON");
-        read("(");
         Expression condition = readExpression();
         command.setOnCondition(condition);
-        read(")");
 
         read("WHEN");
         boolean matched = readIf("MATCHED");

h2/src/test/org/h2/test/db/TestMergeUsing.java

@@ -166,7 +166,7 @@ public class TestMergeUsing extends TestDb implements Trigger {
                 GATHER_ORDERED_RESULTS_SQL,
                 "SELECT X AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(1,3) WHERE X<0",
                 0,
-                "expected \"WHEN\"");
+                "WHEN\"");
         // Two updates to same row - update and delete together - emptying the
         // parent table
         testMergeUsing(

h2/src/test/org/h2/test/scripts/dml/mergeUsing.sql

@@ -118,7 +118,7 @@ DROP TABLE DEST_TABLE;
 CREATE TABLE TEST(C1 INT, C2 INT, C3 INT);
 > ok
 
-MERGE INTO TEST USING DUAL ON (C1 = 11 AND C2 = 21)
+MERGE INTO TEST USING DUAL ON C1 = 11 AND C2 = 21
     WHEN NOT MATCHED THEN INSERT (C1, C2, C3) VALUES (11, 21, 31)
     WHEN MATCHED THEN UPDATE SET C3 = 31;
 > update count: 1
@@ -135,7 +135,7 @@ SELECT * FROM TEST ORDER BY C1, C2;
 > 11 22 32
 > rows (ordered): 2
 
-MERGE INTO TEST USING DUAL ON (C1 = 11 AND C2 = 21)
+MERGE INTO TEST USING DUAL ON C1 = 11 AND C2 = 21
     WHEN NOT MATCHED THEN INSERT (C1, C2, C3) VALUES (11, 21, 33)
     WHEN MATCHED THEN UPDATE SET C3 = 33;
 > update count: 1