mybatis+oracle添加数据时如果数据存在就更新，如果不存在就插入

判断需要插入的数据是否存在，如果不存在就更新

<insert id="saveBatch" parameterType="java.util.List" >  
MERGE INTO 表名 T  
USING ( 
<foreach collection="list" item="item" index="index" separator="union" >
SELECT SYS_GUID() AS CODE,
#{item.createDate,jdbcType=VARCHAR} AS CREATE_DATE,
#{item.createBy,jdbcType=VARCHAR} AS CREATE_BY,
#{item.flagDel,jdbcType=CHAR} AS FLAG_DEL,
#{item.flagDisplay,jdbcType=CHAR} AS FLAG_DISPLAY,
#{item.sort,jdbcType=DECIMAL} AS SORT FROM DUAL
</foreach>) T1  
ON (T1./*判断数据是否重复的字段*/= T./*判断数据是否重复的字段*/ AND T1./*判断数据是否重复的字段*/ = T./*判断数据是否重复的字段*/)
/*数据存在*/
WHEN MATCHED THEN
UPDATE SET T./*需要更新的字段*/=T1/*需要更新的字段*/ 
/*数据不存在*/
WHEN NOT MATCHED THEN
INSERT
(CODE,CREATE_DATE,CREATE_BY,FLAG_DEL,FLAG_DISPLAY,SORT)
VALUES
  (T1.CODE,T1.CREATE_DATE,T1.CREATE_BY,T1.FLAG_DEL,T1.FLAG_DISPLAY,T1.SORT) 

</insert>   

<insert id="batchSave" parameterType="java.util.List">
MERGE INTO RES_SCHOOL_CLUB t
USING (
<foreach collection="list" item="item" index="index" separator="union" >
select #{item.id,jdbcType=VARCHAR} ID,
#{item.clsSchoolId,jdbcType=VARCHAR} CLS_SCHOOL_ID,
#{item.originSchoolId,jdbcType=VARCHAR} ORIGIN_SCHOOL_ID,
#{item.resourceId,jdbcType=VARCHAR} RESOURCE_ID,
#{item.clsClubId,jdbcType=VARCHAR} CLS_CLUB_ID,
#{item.baseAreaId,jdbcType=VARCHAR} BASE_AREA_ID,
#{item.createTime,jdbcType=TIMESTAMP} CREATE_TIME
from dual
</foreach>) t1
ON (t.CLS_SCHOOL_ID =  t1.CLS_SCHOOL_ID AND t.RESOURCE_ID = t1.RESOURCE_ID)
WHEN MATCHED THEN
UPDATE SET t.CREATE_TIME = t1.CREATE_TIME
WHEN NOT MATCHED THEN
INSERT(ID, CLS_SCHOOL_ID, ORIGIN_SCHOOL_ID, RESOURCE_ID, CLS_CLUB_ID, BASE_AREA_ID, CREATE_TIME)
VALUES (t1.ID, t1.CLS_SCHOOL_ID, t1.ORIGIN_SCHOOL_ID, t1.RESOURCE_ID, t1.CLS_CLUB_ID, t1.BASE_AREA_ID, t1.CREATE_TIME)
</insert>