UpSert功能：
MERGE <hint> INTO <table_name>
USING <table_view_or_query>
ON (<condition>)
WHEN MATCHED THEN <update_clause>
WHEN NOT MATCHED THEN <insert_clause>;
MultiTable Inserts功能：
Multitable inserts allow a single INSERT INTO .. SELECT statement to conditionally, or non-conditionally, insert into multiple tables. This
statement reduces table scans and PL/SQL code necessary for performing multiple conditional inserts compared to previous versions. It's
main use is for the ETL process in data warehouses where it can be parallelized and/or convert non-relational data into a relational format:
-- Unconditional insert into ALL tables
INSERT ALL
INTO sal_history VALUES(empid,hiredate,sal)
INTO mgr_history VALUES(empid,mgr,sysdate)
SELECT employee_id EMPID, hire_date HIREDATE, salary SAL, manager_id MGR
from employees WHERE employee_id > 200;
-- Pivoting insert to split non-relational data
INSERT ALL
INTO Sales_info VALUES (employee_id,week_id,sales_MON)
INTO Sales_info VALUES (employee_id,week_id,sales_TUE)
INTO Sales_info VALUES (employee_id,week_id,sales_WED)
INTO Sales_info VALUES (employee_id,week_id,sales_THUR)
INTO Sales_info VALUES (employee_id,week_id, sales_FRI)
SELECT EMPLOYEE_ID, week_id, sales_MON, sales_TUE,
sales_WED, sales_THUR,sales_FRI
from Sales_source_data;
-- Conditionally insert into ALL tables
INSERT ALL
WHEN SAL>10000 THEN
INTO sal_history VALUES(EMPID,HIREDATE,SAL)
WHEN MGR>200 THEN
INTO mgr_history VALUES(EMPID,MGR,SYSDATE)
SELECT employee_id EMPID, hire_date HIREDATE, salary SAL, manager_id MGR
from employees WHERE employee_id > 200;
-- Insert into the FIRST table with a matching condition
INSERT FIRST
WHEN SAL > 25000THEN
INTO special_sal VALUES(DEPTID,SAL)
WHEN HIREDATE like ('%00%') THEN
INTO hiredate_history_00 VALUES(DEPTID,HIREDATE)
WHEN HIREDATE like ('%99%') THEN
INTO hiredate_history_99 VALUES(DEPTID,HIREDATE)
ELSE
INTO hiredate_hi
