Do not create temporary Merge for MergeUsing

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

@@ -1397,18 +1397,17 @@ public class Parser {
 
 
     private Prepared parseMerge() {
-        Merge command = new Merge(session);
-        currentPrepared = command;
         int start = lastParseIndex;
         read("INTO");
         List<String> excludeIdentifiers = Arrays.asList("USING", "KEY", "VALUES");
         TableFilter targetTableFilter = readSimpleTableFilter(0, excludeIdentifiers);
-        command.setTargetTableFilter(targetTableFilter);
-        Table table = command.getTargetTable();
-
         if (readIf("USING")) {
-            return parseMergeUsing(command, start);
+            return parseMergeUsing(targetTableFilter, start);
         }
+        Merge command = new Merge(session);
+        currentPrepared = command;
+        command.setTargetTableFilter(targetTableFilter);
+        Table table = command.getTargetTable();
         if (readIf(OPEN_PAREN)) {
             if (isSelect()) {
                 command.setQuery(parseSelect());
@@ -1434,8 +1433,8 @@ public class Parser {
         return command;
     }
 
-    private MergeUsing parseMergeUsing(Merge oldCommand, int start) {
-        MergeUsing command = new MergeUsing(oldCommand);
+    private MergeUsing parseMergeUsing(TableFilter targetTableFilter, int start) {
+        MergeUsing command = new MergeUsing(session, targetTableFilter);
         currentPrepared = command;
 
         if (readIf(OPEN_PAREN)) {

h2/src/main/org/h2/command/dml/MergeUsing.java

@@ -15,6 +15,7 @@ import org.h2.api.Trigger;
 import org.h2.command.CommandInterface;
 import org.h2.command.Prepared;
 import org.h2.engine.Right;
+import org.h2.engine.Session;
 import org.h2.expression.ConditionAndOr;
 import org.h2.expression.Expression;
 import org.h2.expression.ExpressionColumn;
@@ -32,7 +33,7 @@ import org.h2.value.Value;
 
 /**
  * This class represents the statement syntax
- * MERGE table alias USING...
+ * MERGE INTO table alias USING...
  *
  * It does not replace the existing MERGE INTO... KEYS... form.
  *
@@ -119,12 +120,10 @@ public class MergeUsing extends Prepared {
     private int sourceQueryRowNumber;
 
 
-    public MergeUsing(Merge merge) {
-        super(merge.getSession());
-
-        // bring across only the already parsed data from Merge...
-        this.targetTable = merge.getTargetTable();
-        this.targetTableFilter = merge.getTargetTableFilter();
+    public MergeUsing(Session session, TableFilter targetTableFilter) {
+        super(session);
+        this.targetTable = targetTableFilter.getTable();
+        this.targetTableFilter = targetTableFilter;
     }
 
     @Override