将mysql查询的结果插入现有表中

You've got to use an alias name for your UNION, but you've got to provide an JOIN condition for your right join too. Probably you want to use:

INSERT INTO Table1
select a.* from Table1    
right join    
(
    select
        `timestamp`
      , phase_1
      , phase_2
      , phase_3
    from Table1

    union

    select
        date(`timestamp`)
      , 0
      , 1
      , 2
    from Table1

    order by 
        `timestamp`
) as a
ON DATE(a.timestamp) = DATE(Table1.timestamp)

Remarks:

What is the difference between Left, Right, Outer and Inner Joins? provides a very good explanation of the different joins.

An outer join needs a join condition, an inner join without a condition is the same as an CROSS JOIN, the cartesian product of both tables (most times one wants to avoid this - but not ever).

If you use a SELECT statement, that works perfectly as SELECT statement alone in a join, then the result of this SELECT statement changes into a derived table and you've got to give this derived table a name so you can use the columns of the derived table.

I hope it will be a little bit more clear now.

A better (more efficient) way to write this query is to remove the union and use union all and to remove the join. The basic query you want seems to be:

select `timestamp`, phase_1, phase_2, phase_3
from Table1
union all
select date(`timestamp`), 0, 1, 2
from Table1 t1
group by date(`timestamp`)
having not exists (select 1 from table1 tt1 where tt1.timestamp = date(t1.timestamp))
order by  `timestamp`;

The group by and having clauses in the second query prevent duplicates, if the value already appears in the table. Honestly, though, it is probably better to have a unique constraint on timestamp.

If you want to insert rows into the table, you only need the second portion of the query:

INSERT INTO Table1(timestamp, phase_1, phase_2, phase_3)
    select distinct date(`timestamp`), 0, 1, 2
    from Table1
    group by date(`timestamp`)
    having not exists (select 1 from table1 tt1 where tt1.timestamp = date(t1.timestamp));

The original data is already there.

To insert a "dummy" timestamp for days not in the table, you need a way to generate rows with those values. This can be a pain in MySQL. But, if you have a calendar table that has all the dates, you can do something like:

INSERT INTO Table1(timestamp, phase_1, phase_2, phase_3)
    select c.dte, 0, 1, 2
    from calendar c join
         (select min(date(timestamp)) as mind, max(date(timestmp)) as maxd
          from Table1
         ) tmm
         on c.dte between tmm.mind and tmm.maxd and tmm.mind left join
         Table1 t1
         on date(t1.timestamp) = c.dte
    where t1.timestamp is null;