如何获取MERGE操作中UPDATE行数和INSERT行数

在进行MERGE操作的时候，如何取得更新的行数和插入的行数？

在进行MERGE操作的时候，如何取得更新的行数和插入的行数？

首先创建测试表如下：
CREATE TABLE emp_source AS
SELECT * FROM emp; -- 14 rows

CREATE TABLE emp_target AS
SELECT * FROM emp_source WHERE ROWNUM -- 8 rows

创建用于获取插入行数的包：
CREATE OR REPLACE PACKAGE merge_demo AS
FUNCTION merge_counter RETURN PLS_INTEGER;
FUNCTION get_merge_insert_count RETURN PLS_INTEGER;
PROCEDURE reset_counters;
END merge_demo;
/

CREATE OR REPLACE PACKAGE BODY merge_demo AS
g_insert_counter PLS_INTEGER NOT NULL := 0;

FUNCTION merge_counter RETURN PLS_INTEGER IS
BEGIN
g_insert_counter := g_insert_counter + 1;--注意：此函数永远返回0，即此函数不影--响插入，，但在每次插入都进行计数。此是关键。
RETURN 0;
END merge_counter;

FUNCTION get_merge_insert_count RETURN PLS_INTEGER IS
BEGIN
RETURN g_insert_counter;
END get_merge_insert_count;

PROCEDURE reset_counters IS
BEGIN
g_insert_counter := 0;
END reset_counters;

END merge_demo;
/

以下代码通过上述包获取插入行数，并结合使用SQL%ROWCOUNT取得更新行数：
BEGIN
MERGE INTO emp_target et
USING ( SELECT * FROM emp_source ) es
ON ( et.empno = es.empno )
WHEN MATCHED THEN
UPDATE
SET et.ename = es.ename, et.sal = es.sal, et.mgr = es.mgr, et.deptno = es.deptno
WHEN NOT MATCHED THEN
INSERT ( et.empno, et.ename, et.sal, et.mgr, et.deptno)
VALUES ( CASE merge_demo.merge_counter
WHEN 0 THEN es.empno
END
, es.ename, es.sal, es.mgr, es.deptno
);
DBMS_OUTPUT.PUT_LINE( 'Total ' || SQL%ROWCOUNT || ' rows merged.' );
DBMS_OUTPUT.PUT_LINE(merge_demo.get_merge_insert_count || ' rows inserted.');
DBMS_OUTPUT.PUT_LINE( SQL%ROWCOUNT - merge_demo.get_merge_insert_count || ' rows updated.');
merge_demo.reset_counters;
END;