Added match-select query for ROWID checking

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

@@ -1126,7 +1126,7 @@ public class Parser {
     private MergeUsing parseMergeUsing(Merge oldCommand, int start) {
         MergeUsing command = new MergeUsing(oldCommand);
         currentPrepared = command;
-        
+                
         if (readIf("(")) {
             /* a select query is supplied */
             if (isSelect()) {
@@ -1162,7 +1162,7 @@ public class Parser {
         Expression condition = readExpression();
         command.setOnCondition(condition);
         read(")");
-        
+                
         if(readIfAll("WHEN","MATCHED","THEN")){
             int startMatched = lastParseIndex;
             if (readIf("UPDATE")){
@@ -1192,6 +1192,33 @@ public class Parser {
         }
 
         setSQL(command, "MERGE", start);
+        
+        // build and prepare the targetMatchQuery ready to test each rows existence in the target table (using source row to match)
+        StringBuffer targetMatchQuerySQL = new StringBuffer("SELECT _ROWID_ FROM "+command.getTargetTable().getName());
+        if(command.getTargetTableFilter().getTableAlias()!=null){
+            targetMatchQuerySQL.append(" AS "+command.getTargetTableFilter().getTableAlias());
+        }
+        targetMatchQuerySQL.append(" WHERE "+command.getOnCondition().getSQL());
+//        Select preparedTargetMatchQuery = new Select(session);
+//        preparedTargetMatchQuery.addTableFilter(command.getTargetTableFilter(), true/*isTop*/);
+//        preparedTargetMatchQuery.addTableFilter(command.getSourceTableFilter(), false/*isTop - not top table scan*/);
+//        preparedTargetMatchQuery.setSQL(targetMatchQuerySQL.toString());
+//        ArrayList<Expression> selectList = New.arrayList();
+//        //Database db = session == null ? null : session.getDatabase();
+//        selectList.add(new ExpressionColumn(session.getDatabase(), command.getTargetTableFilter().getTable().getRowIdColumn()));
+//        preparedTargetMatchQuery.setExpressions(selectList);
+//        preparedTargetMatchQuery.init();
+          command.setTargetMatchQuery((Select)parse(targetMatchQuerySQL.toString()));
+        
+//        Select command = new Select(session);
+//        currentSelect = command;
+//        TableFilter filter = parseValuesTable(0);
+//        ArrayList<Expression> list = New.arrayList();
+//        list.add(new Wildcard(null, null));
+//        command.setExpressions(list);
+//        command.addTableFilter(filter, true);
+//        command.init();        
+        
         return command;
     }
 

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

@@ -168,6 +168,10 @@ public class Select extends Query {
         }
     }
 
+    public Expression getCondition() {
+        return condition;
+    }
+
     private LazyResult queryGroupSorted(int columnCount, ResultTarget result) {
         LazyResultGroupSorted lazyResult = new LazyResultGroupSorted(expressionArray, columnCount);
         if (result == null) {

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

@@ -182,7 +182,17 @@ public class TestMergeUsing extends TestBase {
                 "SELECT X AS ID, 'Marcy'||X||X AS NAME FROM SYSTEM_RANGE(2,2) UNION ALL SELECT X AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(3,3)",
                 3,
                 "No references to source columns found in ON clause"
-                );        
+                );      
+        // Insert does not insert correct values with respect to ON condition (inserts ID value above 100, instead)
+        testMergeUsingException(
+                "CREATE TABLE PARENT AS (SELECT 1 AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(4,4) );"+
+                        "CREATE TABLE SOURCE AS (SELECT X AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(1,3)  );",
+                "MERGE INTO PARENT USING SOURCE ON (PARENT.ID = SOURCE.ID) WHEN MATCHED THEN UPDATE SET PARENT.NAME = SOURCE.NAME||SOURCE.ID WHERE PARENT.ID = 2 DELETE WHERE PARENT.ID = 1 WHEN NOT MATCHED THEN INSERT (ID, NAME) VALUES (SOURCE.ID+100, SOURCE.NAME)",
+                GATHER_ORDERED_RESULTS_SQL,
+                "SELECT X AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(4,4)",
+                1,
+                "Expected to find key after row inserted, but none found. Insert does not match ON condition."
+                );              
        }
 
     /**