复杂的join 例子

join相同表

java

List<SysUser> list=QueryChain.of(sysUserMapper)
    .innerJoin(SysUser::getId,1,SysUser::getRole_id,2)
    .list();

join子查询

java

SubQuery subQuery=SubQuery.create("sub")
    .select(SysRole.class)
    .from(SysRole.class)
    .eq(SysRole::getId,1);

List<SysUser> list=QueryChain.of(sysUserMapper)
    .select(SysUser.class)
    .from(SysUser.class)
    .innerJoin(SysUser.class,subQuery,on->on.eq(SysUser::getRole_id,subQuery.$outerField(SysRole::getId)))
    .list();

返回2张相同表字段

java

List<SysUserVO> list=QueryChain.of(sysUserMapper)
    .select(SysUser.class)
    .select(SysUser.class,2)   
    .from(SysUser.class)
    .innerJoin(SysUser::getId,1,SysUser::getRole_id,2)
    .returnType(SysUserVO.class)    
    .list();