Oracle 使用MERGE INTO 语句更新数据

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/*Merge into 详细介绍
MERGE语句是Oracle9i新增的语法，用来合并UPDATE和INSERT语句。
通过MERGE语句，根据一张表或子查询的连接条件对另外一张表进行查询，
连接条件匹配上的进行UPDATE，无法匹配的执行INSERT。
这个语法仅需要一次全表扫描就完成了全部工作，执行效率要高于INSERT＋UPDATE。
*/
/*语法：
MERGE [INTO [schema .] table [t_alias]
USING [schema .] { table | view | subquery } [t_alias]
ON ( condition )
WHEN MATCHED THEN merge_update_clause
WHEN NOT MATCHED THEN merge_insert_clause;
*/

merge into usersusing teamon (users.user_id = team.t_id)when matched then  update set users.user_name = team.doctornamewhen not matched then  insert  values    (team.doctorid,     team.doctorid,     '8736F1C243E3B14941A59FF736E1B5A8',     team.doctorname,     sysdate,     'T',     ' ',     team.deptid,     'b319dac7-2c5c-496a-bc36-7f3e1cc066b8');

或

merge into T_EHR_CONTENTS  t                                                                                             using (select * from T_INTRA_CONTENTS  where 1=1) tt                                                                       on (t.XWEHR_ID = tt.CONTENT_ID)                                                                                  when matched then                                                                                          update                                                                                                          set t.CONTENT_TITLE        = tt.CONTENT_TITLE,                                                                              t.AUTHOR               = tt.AUTHOR ,                                      t.CONTENT_SUMMARY      = tt.POLICY_SUMMARY,

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