Inserting the results of a mysql query into existing table - php

Question

I have a an existing table with timestamps and other values and I wanted to create dummy timestamps for each day in the table
For example
timestamp phase_1 phase_2 phase_3
2014-03-04 12:00:00 0 0 0
2014-03-05 02:00:00 0 0 0
2014=03-06 01:00:00 0 0 0
2014-03-07 00:00:00 0 3 1
should result to
timestamp phase_1 phase_2 phase_3
2014-03-04 00:00:00 0 0 0 --<< new
2014-03-04 12:00:00 0 0 0
2014-03-05 00:00:00 0 0 0 --<< new
2014-03-05 02:00:00 0 0 0
2014-03-06 00:00:00 0 0 0 --<< new
2014-03-06 01:00:00 0 0 0
2014-03-07 00:00:00 0 3 1
The following query works fine
`select * 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`) `
but I am not able to insert the result into the exisiting database
using the following query
`INSERT into Table1
select * 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`) `
Which i think is correct but i get a
: Every derived table must have its own alias: error which i am not sure on how to solve
Here is the fiddle enter link description here
Also, will it be possible to insert dummy timestamp and values for days which are not there at all in the table?
Suppose there are two days between the first and last rows in the table and there are no timestamps for those days in the table, will it be possible to add those two dates into the table.
I want to avoid trigger and procedures if possible as I am not at all familiar with them and since the table is dynamically generated, i think it wont be possible to use them.

Answer 1

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.

Answer 2

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;