Corrected "MERGE INTO" parsing for more complicated statements.

Specifically:
* Changed "Condition" to "Expression" for the "ON" clause -- this is
  needed to handle "ON" clauses that have "a = y AND b = z" or other
  more complicated expressions (basically the same as the "ON" clause
  in a SELECT query).
* Also changed the "WHERE" and "DELETE WHERE" clauses in the same
  fashion ('Condition' becomes 'Expression'), as they too support
  multiple conditions.
* Corrected the toString on the MergeUpdate clause, which was missing a
  comma between the fields.
* Added a new, more complicated MERGE INTO statement to the MergeTest
  class.

Author: davelindquist-egistix

src/main/java/net/sf/jsqlparser/statement/merge/MergeUpdate.java

@@ -73,6 +73,9 @@ public String toString() {
         StringBuilder b = new StringBuilder();
         b.append(" WHEN MATCHED THEN UPDATE SET ");
         for (int i = 0; i < columns.size(); i++) {
+			if (i != 0) {
+				b.append(", ");
+			}
             b.append(columns.get(i).toString()).append(" = ").append(values.get(i).toString());
         }
         if (whereCondition != null) {

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -590,7 +590,7 @@ Statement Merge() : {
         ( table=Table() { merge.setUsingTable(table); } 
             | "(" select=SubSelect() { merge.setUsingSelect(select); } ")" )
      [ alias = Alias() { merge.setUsingAlias(alias); } ] <K_ON> 
-       "(" condition = Condition() { merge.setOnCondition(condition); } ")"
+       "(" condition = Expression() { merge.setOnCondition(condition); } ")"
 
     [ LOOKAHEAD(2) update = MergeUpdateClause() { merge.setMergeUpdate(update); } ]
 
@@ -616,8 +616,8 @@ MergeUpdate MergeUpdateClause() : {
 
         { mu.setColumns(columns); mu.setValues(expList); }
 
-        [ <K_WHERE> condition = Condition() { mu.setWhereCondition(condition); }]
-        [ <K_DELETE> <K_WHERE> condition = Condition() { mu.setDeleteWhereCondition(condition); } ]
+        [ <K_WHERE> condition = Expression() { mu.setWhereCondition(condition); }]
+        [ <K_DELETE> <K_WHERE> condition = Expression() { mu.setDeleteWhereCondition(condition); } ]
 
         { return mu; }
 }

src/test/java/net/sf/jsqlparser/test/merge/MergeTest.java

@@ -62,4 +62,91 @@ public void testMergeIssue232() throws JSQLParserException {
 
         assertSqlCanBeParsedAndDeparsed(sql, true);
     }
+
+    @Test
+    public void testComplexOracleMergeIntoStatement() throws JSQLParserException {
+        String sql = "MERGE INTO DestinationValue Dest USING\n"
+        		+ "(SELECT TheMonth ,\n"
+        		+ "  IdentifyingKey ,\n"
+        		+ "  SUM(NetPrice) NetPrice ,\n"
+        		+ "  SUM(NetDeductionPrice) NetDeductionPrice ,\n"
+        		+ "  MAX(CASE RowNumberMain WHEN 1 THEN QualityIndicator ELSE NULL END) QualityIndicatorMain ,\n"
+        		+ "  MAX(CASE RowNumberDeduction WHEN 1 THEN QualityIndicator ELSE NULL END) QualityIndicatorDeduction \n"
+        		+ "FROM\n"
+        		+ "  (SELECT pd.TheMonth ,\n"
+        		+ "    COALESCE(pd.IdentifyingKey, 0) IdentifyingKey ,\n"
+        		+ "    COALESCE(CASE pd.IsDeduction WHEN 1 THEN NULL ELSE ConvertedCalculatedValue END, 0) NetPrice ,\n"
+        		+ "    COALESCE(CASE pd.IsDeduction WHEN 1 THEN ConvertedCalculatedValue ELSE NULL END, 0) NetDeductionPrice ,\n"
+        		+ "    pd.QualityIndicator ,\n"
+        		+ "    row_number() OVER (PARTITION BY pd.TheMonth , pd.IdentifyingKey ORDER BY COALESCE(pd.QualityMonth, to_date('18991230', 'yyyymmdd')) DESC ) RowNumberMain ,\n"
+        		+ "    NULL RowNumberDeduction\n"
+        		+ "  FROM PricingData pd\n"
+        		+ "  WHERE pd.ThingsKey      IN (:ThingsKeys)\n"
+        		+ "  AND pd.TheMonth       >= :startdate\n"
+        		+ "  AND pd.TheMonth       <= :enddate\n"
+        		+ "  AND pd.IsDeduction = 0\n"
+        		+ "  UNION ALL\n"
+        		+ "  SELECT pd.TheMonth ,\n"
+        		+ "    COALESCE(pd.IdentifyingKey, 0) IdentifyingKey ,\n"
+        		+ "    COALESCE(CASE pd.IsDeduction WHEN 1 THEN NULL ELSE ConvertedCalculatedValue END, 0) NetPrice ,\n"
+        		+ "    COALESCE(CASE pd.IsDeduction WHEN 1 THEN ConvertedCalculatedValue ELSE NULL END, 0) NetDeductionPrice ,\n"
+        		+ "    pd.QualityIndicator ,\n"
+        		+ "    NULL RowNumberMain ,\n"
+        		+ "    row_number() OVER (PARTITION BY pd.TheMonth , pd.IdentifyingKey ORDER BY COALESCE(pd.QualityMonth, to_date('18991230', 'yyyymmdd')) DESC ) RowNumberDeduction \n"
+        		+ "  FROM PricingData pd\n"
+        		+ "  WHERE pd.ThingsKey       IN (:ThingsKeys)\n"
+        		+ "  AND pd.TheMonth        >= :startdate\n"
+        		+ "  AND pd.TheMonth        <= :enddate\n"
+        		+ "  AND pd.IsDeduction <> 0\n"
+        		+ "  )\n"
+        		+ "GROUP BY TheMonth ,\n"
+        		+ "  IdentifyingKey\n"
+        		+ ") Data ON ( Dest.TheMonth = Data.TheMonth \n"
+        		+ "            AND COALESCE(Dest.IdentifyingKey,0) = Data.IdentifyingKey )\n"
+        		+ "WHEN MATCHED THEN\n"
+        		+ "  UPDATE\n"
+        		+ "  SET NetPrice        = ROUND(Data.NetPrice, PriceDecimalScale) ,\n"
+        		+ "    DeductionPrice    = ROUND(Data.NetDeductionPrice, PriceDecimalScale) ,\n"
+        		+ "    SubTotalPrice     = ROUND(Data.NetPrice + (Data.NetDeductionPrice * Dest.HasDeductions), PriceDecimalScale) ,\n"
+        		+ "    QualityIndicator  =\n"
+        		+ "    CASE Dest.HasDeductions\n"
+        		+ "      WHEN 0\n"
+        		+ "      THEN Data.QualityIndicatorMain\n"
+        		+ "      ELSE\n"
+        		+ "        CASE\n"
+        		+ "          WHEN COALESCE(Data.CheckMonth1, to_date('18991230', 'yyyymmdd'))> COALESCE(Data.CheckMonth2,to_date('18991230', 'yyyymmdd'))\n"
+        		+ "          THEN Data.QualityIndicatorMain\n"
+        		+ "          ELSE Data.QualityIndicatorDeduction\n"
+        		+ "        END\n"
+        		+ "    END ,\n"
+        		+ "    RecUser = :recuser ,\n"
+        		+ "    RecDate = :recdate\n"
+    			+ "  WHERE 1 =1\n"
+    			+ "  AND IsImportant = 1\n"
+    			+ "  AND COALESCE(Data.SomeFlag,-1) <> COALESCE(ROUND(Something, 1),-1)\n"
+    			+ "  DELETE WHERE\n"
+    			+ "  IsImportant = 0\n"
+    			+ "  OR COALESCE(Data.SomeFlag,-1) = COALESCE(ROUND(Something, 1),-1)\n"
+    			+ " WHEN NOT MATCHED THEN \n"
+    			+ "  INSERT\n"
+    			+ "    (\n"
+    			+ "      TheMonth ,\n"
+    			+ "      ThingsKey ,\n"
+    			+ "      IsDeduction ,\n"
+    			+ "      CreatedAt \n"
+    			+ "    )\n"
+    			+ "    VALUES\n"
+    			+ "    (\n"
+    			+ "      Data.TheMonth ,\n"
+    			+ "      Data.ThingsKey ,\n"
+    			+ "      Data.IsDeduction ,\n"
+    			+ "      SYSDATE\n"
+    			+ "    )\n";
+
+        Statement statement = CCJSqlParserUtil.parse(sql);
+        
+        System.out.println(statement.toString());
+        
+        assertSqlCanBeParsedAndDeparsed(sql, true);
+    }
 }