MySQL : Update Table upon certain conditions - mysql

Question

I have 2 tables , master and current table( refreshed very hr).
Both the table shave same structure:
Chk | description |state | date
I need to update / append ( add the new row ) into the master table if :
1) rows that have new IDs or
2) if a particular variable ( 'state' in this case) has changed. I tried to do it using below without success :
INSERT into AGILE_TICKETS_DLY
SELECT * FROM CURR_AGILE_TICKETS curr
WHERE EXISTS (SELECT * FROM AGILE_TICKETS_DLY mstr
WHERE (curr.chk != mstr.chk) OR ( curr.chk = mstr.chk and
mstr.state != curr.state))
Any pointers on how to achieve this ?

Answer 1

You can try this pair of queries:
-- insert new rows
insert into agile_tickets_dly
select * from curr_agile_tickets
where chk not in (select chk from agile_tickets_dly);
-- update updated rows
update agile_tickets_dly x
join
(
select b.chk chk,b.description description,b.state state,b.date date
from agile_tickets_dly a, curr_agile_tickets b
where
a.chk=b.chk and
(a.description != b.description or a.state != b.state or a.date != b.date)
) y
on x.chk=y.chk
set x.description = y.description, x.state= y.state, x.date = y.date;
Illustration:
select * from agile_tickets_dly;
+------+-------------+---------+------------+
| chk | description | state | date |
+------+-------------+---------+------------+
| 0 | desc-0 | state-1 | 01-01-2017 |
| 1 | desc-1 | state-1 | 01-01-2018 |
| 2 | desc-2 | state-2 | 01-02-2018 |
| 3 | desc-3 | state-3 | 01-03-2018 |
+------+-------------+---------+------------+
-- one new row with chk=4, three updated rows with chk=1,2,3
select * from curr_agile_tickets;
+------+----------------+-----------------+----------------+
| chk | description | state | date |
+------+----------------+-----------------+----------------+
| 0 | desc-0 | state-1 | 01-01-2017 |
| 1 | desc-1 | state-1 | date-1-updated |
| 2 | desc-2-updated | state-2 | 01-02-2018 |
| 3 | desc-3 | state-3-updated | 01-03-2018 |
| 4 | desc-4 | state-4 | 01-04-2018 |
+------+----------------+-----------------+----------------+
-- after executing the two queries
select * from agile_tickets_dly;
+------+----------------+-----------------+----------------+
| chk | description | state | date |
+------+----------------+-----------------+----------------+
| 0 | desc-0 | state-1 | 01-01-2017 |
| 1 | desc-1 | state-1 | date-1-updated |
| 2 | desc-2-updated | state-2 | 01-02-2018 |
| 3 | desc-3 | state-3-updated | 01-03-2018 |
| 4 | desc-4 | state-4 | 01-04-2018 |
+------+----------------+-----------------+----------------+

Answer 2

I tried to do this in 2 separate steps:
1) First I append all new rows with IDs : this worked
INSERT into AGILE_TICKETS_DLY
SELECT * FROM CURR_AGILE_TICKETS curr
WHERE not EXISTS (SELECT * FROM AGILE_TICKETS_DLY mstr
WHERE (curr.chk = mstr.chk));
But then, I tried to do below got an error
2) Then replace the 'State' variable with new value:
INSERT into AGILE_TICKETS_DLY_1 (state)
SELECT state
from CURR_AGILE_TICKETS_1 curr
where exists ( select * from AGILE_TICKETS_DLY_1 mstr where curr.chk =
mstr.chk);
But this gives me an error :
SQL Error (1364) : Field 'chk' doesn't have a default value.
What does that mean ?