Remove target row match on insert restriction from MERGE USING

h2/src/docsrc/html/changelog.html

@@ -21,6 +21,8 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Issue #1491: Unnecessary restriction on MERGE USING statement when ON predicate doesn't match inserted row
+</li>
 <li>Issue #1490: NullPointerException when running invalid MERGE statement
 </li>
 <li>Issue #1488: Improve documentation of window and some other functions

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

@@ -6,7 +6,6 @@
 package org.h2.command.dml;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 
@@ -214,15 +213,7 @@ public class MergeUsing extends Prepared {
             }
         } else {
             if (insertCommand != null) {
-                int count = insertCommand.update();
-                if (!isTargetRowFound()) {
-                    throw DbException.get(ErrorCode.GENERAL_ERROR_1,
-                            "Expected to find key after row inserted, but none found. "
-                                    + "Insert does not match ON condition.:"
-                                    + targetTable.getSQL() + ":source row="
-                                    + Arrays.asList(sourceRow.getValueList()));
-                }
-                countUpdatedRows += count;
+                countUpdatedRows += insertCommand.update();
             }
         }
     }

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

@@ -196,25 +196,6 @@ public class TestMergeUsing extends TestDb implements Trigger {
                 "SELECT 1 AS ID, 'Marcy'||X||X UNION ALL SELECT 1 AS ID, 'Marcy2'",
                 2);
 
-        // Multiple update on same row: SQL standard says duplicate or repeated
-        // updates in same statement should cause errors -but because first row
-        // is updated, delete then insert it's considered different
-        // One insert, one update one delete happens (on same row, which is
-        // okay), then another update (which is illegal)target table missing PK,
-        // no source or target alias
-        testMergeUsingException(
-                "CREATE TABLE PARENT AS (SELECT X AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(1,1) );"
-                        + "CREATE TABLE SOURCE AS (SELECT 1 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, SOURCE.NAME)",
-                GATHER_ORDERED_RESULTS_SQL,
-                "SELECT 1 AS ID, 'Marcy'||X||X UNION ALL SELECT 1 AS ID, 'Marcy2'",
-                3,
-                "Unique index or primary key violation: \"Merge using " +
-                "ON column expression, duplicate _ROWID_ target record " +
-                "already updated, deleted or inserted:_ROWID_=2:in:PUBLIC.PARENT:conflicting source row number:2");
         // Duplicate key updated 3 rows at once, only 1 expected
         testMergeUsingException(
                 "CREATE TABLE PARENT AS (SELECT 1 AS ID, 'Marcy'||X AS NAME FROM SYSTEM_RANGE(1,3) );"
@@ -251,18 +232,6 @@ public class TestMergeUsing extends TestDb implements Trigger {
                 "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, "Duplicate key updated 3 rows at once, only 1 expected");
-        // 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.");
         // One insert, one update one delete happens, target table missing PK,
         // triggers update all NAME fields
         triggerTestingUpdateCount = 0;

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

@@ -213,3 +213,25 @@ MERGE INTO TEST USING (SELECT 40) ON UNKNOWN_COLUMN = 1 WHEN NOT MATCHED THEN IN
 
 DROP TABLE TEST;
 > ok
+
+CREATE TABLE TEST(ID INT PRIMARY KEY, VALUE INT);
+> ok
+
+INSERT INTO TEST VALUES (1, 10), (2, 20);
+> update count: 2
+
+MERGE INTO TEST USING (SELECT 1) ON (ID < 0)
+    WHEN MATCHED THEN UPDATE SET VALUE = 30
+    WHEN NOT MATCHED THEN INSERT VALUES (3, 30);
+> update count: 1
+
+SELECT * FROM TEST;
+> ID VALUE
+> -- -----
+> 1  10
+> 2  20
+> 3  30
+> rows: 3
+
+DROP TABLE TEST;
+> ok