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mybatis-mp 之多表 join，非常简单

日期：2024-06-24点击：299收藏

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多表join

List<SysUser> list=QueryChain.of(sysUserMapper)
    .select(SysUser.class)
    .from(SysUser.class)
    .join(SysUser.class,SysRole.class)
    .list();

join相同表

List<SysUser> list=QueryChain.of(sysUserMapper)
    .select(SysUser.class)
    .from(SysUser.class)
    .join(SysUser.class,1,SysUser.class,2,on->on.eq(SysUser::getId,1,SysUser::getRole_id,2))
    .list();

join子查询

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)
    .join(SysUser.class,subQuery,on->on.eq(SysUser::getRole_id,subQuery.$(subQuery,SysRole::getId)))
    .list();

返回2张相同表字段

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