Mybatis common summary

1. Parameter injection
1.1 uses the form of #{0}, #{1}, 0 represents the first parameter, 1 represents the second parameter
　public List queryList(String workerId, Integer topNum);

SELECT ID id, WORKER_ID workerId, UPDATE_DATE updateDate　　　FROM USER_RECORDS t　　　WHERE t.WORKER_ID = #{0}　　LIMIT #{1}
1.2Map or encapsulated object, workerId is the key in the map; if it is an object, workerId For attributes in objects, this method is very commonly used
　　public Integer queryCountByWorkerId(Map queryParam);
　public Integer queryCountByWorkerId(@param(“workerId”)String workerId);　　SELECT COUNT(1)　　FROM tableName F　　WHERE F.WORKER_ID = #{workerId}

2. Return
2.1 mapping






　　select ID,CREATE_DATE,WORKERID from tableName

　This way the query statement queries the fields directly It’s just a field in the database, just define the mapped column
2.2 Return the object directly
　　select ID id,CREATE_DATE createDate,WORKERID workerId from tableName

3. Execute native sql
3.1sql parameters:　public class ParamVo {　　private String sql;　　　//getter setter omitted

　　}

3.2 interface:
　 /**
　 * @Function description: Create

　 * @return
　*/

　 /**
　 * @Function description: Query
　 * @param vo
　 * @return
　*/
public List
> excuteSelectSql(ParamVo vo);

3.3xml:


　　${sql}


　${}Do not compile sql and execute it directly. If you use #{sql}, an error may be reported

4.2 Quote

　　 SELECT COUNT(1)





　　 SELECT ID id, WORKER_ID workerId, UPDATE_DATE updateDate,...