mssql存在更新否则增加的mybatis语句

<update id="synch" parameterType="com.model.PolicyBkQw">
      IF EXISTS
    (
        select _tmp.pindex as c from t_policy_bk_qw _tmp with(nolock,index=u_index_pindex) where _tmp.pindex = #{pindex,jdbcType=VARCHAR}
    )
    
    BEGIN
    
    update t_policy_bk_qw set state=#{state,jdbcType=CHAR}
    ,updatetime = #{updatetime,jdbcType=TIMESTAMP}
    ,seatnum = #{seatnum,jdbcType=INTEGER}
     where pindex = #{pindex,jdbcType=VARCHAR}
    
    END
    
    ELSE

    BEGIN
    
    INSERT INTO t_policy_bk_qw (pindex,[state],updatetime,seatnum) VALUES(
    #{pindex,jdbcType=VARCHAR}
    ,#{state,jdbcType=CHAR}
    ,#{updatetime,jdbcType=TIMESTAMP}
    ,#{seatnum,jdbcType=INTEGER}
    )
    
    END
  </update>

void synch(PolicyBkQw policyBkQw)throws SQLException;