MyBatisPlus中的likeLeft和likeRight

在使用MyBatisPlus来匹配身份证后6位时遇到了likeLeft和likeRight的问题：

likeLeft时匹配最左边还是匹配最右边？

所以来一个简单的测试（通过打印 “成功/失败” 来判断）

MyBatisPlus代码：

    default boolean bindStudent(AppUserBindVO appUserBindVO){
        String idLastSix = appUserBindVO.getIdLastSix(); // 获取 appUserBindVO 对象的后六位字符串
        return exists(new LambdaQueryWrapperX<StudentDO>()
                .eqIfPresent(StudentDO::getStudentNumber,appUserBindVO.getNumber())
                .eqIfPresent(StudentDO::getName,appUserBindVO.getName())
                .eqIfPresent(StudentDO::getMobile,appUserBindVO.getMobile())
                .likeLeft(StudentDO::getIdCard, idLastSix)
        );
    }
    
    
    @Override
    public boolean bindStudent(AppUserBindVO appUserBindVO) {
        if (studentMapper.bindStudent(appUserBindVO)){
            System.out.println("绑定成功");
        }else System.out.println("绑定失败");
        return studentMapper.bindStudent(appUserBindVO);
    }

MySQL：

用Apifox通过身份证后6位请求，绑定成功

用Apifox通过身份证前6位请求，绑定失败

究其源码：

    public Children like(boolean condition, R column, Object val) {
        return this.likeValue(condition, SqlKeyword.LIKE, column, val, SqlLike.DEFAULT);
    }
   public Children likeLeft(boolean condition, R column, Object val) {
        return this.likeValue(condition, SqlKeyword.LIKE, column, val, SqlLike.LEFT);
    }

    public Children likeRight(boolean condition, R column, Object val) {
        return this.likeValue(condition, SqlKeyword.LIKE, column, val, SqlLike.RIGHT);
    }
    
//===============================================================================


    protected Children likeValue(boolean condition, SqlKeyword keyword, R column, Object val, SqlLike sqlLike) {
        return this.maybeDo(condition, () -> {
            this.appendSqlSegments(this.columnToSqlSegment(column), keyword, () -> {
                return this.formatParam((String)null, SqlUtils.concatLike(val, sqlLike));
            });
        });
    }
    
//==============================================================================


    public static String concatLike(Object str, SqlLike type) {
        switch(type) {
        case LEFT:
            return "%" + str;
        case RIGHT:
            return str + "%";
        default:
            return "%" + str + "%";
        }
    }

最后发现 LEFT 是在左边加 “%” , 所以likeLeft匹配的是右边

likeRight则是匹配左边，like则是都可以匹配