I have a table of users that has a column called order that represents the order in they will be elected.
So, for example, the table might look like:
| id | name | order |
|-----|--------|-------|
| 1 | John | 2 |
| 2 | Mike | 0 |
| 3 | Lisa | 1 |
So, say that now Lisa gets destroyed, I would like that in the same transaction that I destroy Lisa, I am able to update the table so the order is still consistent, so the expected result would be:
| id | name | order |
|-----|--------|-------|
| 1 | John | 1 |
| 2 | Mike | 0 |
Or, if Mike were the one to be deleted, the expected result would be:
| id | name | order |
|-----|--------|-------|
| 1 | John | 1 |
| 3 | Lisa | 0 |
How can I do this in PostgreSQL?
If you are just deleting one row, one option uses a cte and the returning clause to then trigger an update
with del as (
delete from mytable where name = 'Lisa'
returning ord
)
update mytable
set ord = ord - 1
from del d
where mytable.ord > d.ord
As a more general approach, I would really recommend trying to renumber the whole table after every delete. This is inefficient, and can get tedious for multi-rows delete.
Instead, you could build a view on top of the table:
create view myview as
select id, name, row_number() over(order by ord) ord
from mytable
Related
I'm trying to fill a table with data to test a system.
I have two tables
User
+----+----------+
| id | name |
+----+----------+
| 1 | Majikaja |
| 2 | User 2 |
| 3 | Markus |
+----+----------+
Goal
+----+----------+---------+
| id | goal | user_id |
+----+----------+---------+
I want to insert into goal one record for every user only using their IDs (they have to exists) and some fixed or random value.
I was thinking in something like this:
INSERT INTO Goal (goal, user_id) values ('Fixed value', select u.id from user u)
So it will generate:
Goal
+----+-------------+---------+
| id | goal | user_id |
+----+-------------+---------+
| 1 | Fixed value | 1 |
| 2 | Fixed value | 2 |
| 3 | Fixed value | 3 |
+----+-------------+---------+
I could just write a simple PHP script to achieve it but I wonder if is it possible to do using raw SQL only.
I have a database full with accounting journals. There is table for accounting journal itself (the accounting journal's metadata) and there is a table for accounting journal line (for each account with its debit or credit).
I have database like this:
+----+---------------+--------+---------+
| ID | JOURNAL_NAME | DEBIT | CREDIT |
+----+---------------+--------+---------+
| | | | |
| 1 | INV/0001 | 100 | 0 |
| | | | |
| 2 | INV/0001 | 0 | 100 |
| | | | |
| 3 | INV/0002 | 200 | 0 |
| | | | |
| 4 | INV/0002 | 0 | 200 |
+----+---------------+--------+---------+
I want to have all journal with the same name to be summed in one, their debits and credits. So from the above table... I want to have a query that makes something like this:
+--------------+--------+---------+
| JOURNAL_NAME | DEBIT | CREDIT |
+--------------+--------+---------+
| | | |
| INV/0001 | 100 | 100 |
| | | |
| INV/0002 | 200 | 200 |
+--------------+--------+---------+
I have tried with:
SELECT DISTINCT ON (accounting_journal.id)
accounting_journal.name,
accounting_journal_line.debit,
accounting_journal_line.credit
FROM accounting_journal_line
JOIN accounting_journal ON accounting_journal.id = accounting_journal_line.move_id
ORDER BY accounting_journal.id ASC
LIMIT 3;
With the above query, I have all the journal and the journal lines. I just need to have the above query to sum the debits and credits for every same accounting_journal.name.
I have tried with SUM() but it always stuck in GROUP BY` clause.
SELECT DISTINCT ON (accounting_journal.id)
accounting_journal.name,
accounting_journal.ref,
accounting_journal_line.name,
SUM(accounting_journal_line.debit),
SUM(accounting_journal_line.credit)
FROM accounting_journal_line
JOIN accounting_journal ON accounting_journal.id = accounting_journal_line.move_id
ORDER BY accounting_journal.id ASC
LIMIT 3;
The error:
Error in query (7): ERROR: column "accounting_journal.name" must appear in the GROUP BY clause or be used in an aggregate function
LINE 2: accounting_journal.name,
I hope I can get assistance or pointer where I need to look at, here. Thanks!
When you are using any aggregation function with normal columns then your have to mention all the non-aggregating column in group by clause,
So try This:
SELECT DISTINCT ON (accounting_journal.id)
accounting_journal.name,
accounting_journal.ref,
accounting_journal_line.name,
SUM(accounting_journal_line.debit),
SUM(accounting_journal_line.credit)
FROM accounting_journal_line
JOIN accounting_journal ON accounting_journal.id = accounting_journal_line.move_id
group by 1,2,3
ORDER BY accounting_journal.id ASC
LIMIT 3;
In your query you are having 3 non-aggregation column so you can mention column number in group by clause to achieve it.
You can use the Sum Window Function, it does not require "group by". So:
select aj.id journal_id
aj.name journal_name,
aj.ref journal_ref,
ajl.name line_name,
sum(ajl.debit) over(partition by aj.id) total_debit,
sum(ajl.credit) over(partition by aj.id) total_credit
from accounting_journal_line ajl
join accounting_journal aj
on aj.id = ajl.move_id
order by aj.id;
See fiddle for a working example.
I have two tables below named sent_table and received_table. I am attempting to mash them together in a query to achieve output_table. All my attempts so far result in a huge amount of duplicates and totally bogus sum values.
I am assuming I would need to use GROUP BY and WHERE to achieve this goal. I want to be able to filter based on the users name.
sent_table
+----+------+-------+----------+
| id | name | value | order_id |
+----+------+-------+----------+
| 1 | dave | 100 | 1 |
| 2 | dave | 200 | 1 |
| 3 | dave | 300 | 2 |
+----+------+-------+----------+
received_table
+----+------+-------+----------+
| id | name | value | order_id |
+----+------+-------+----------+
| 1 | dave | 400 | 1 |
| 2 | dave | 500 | 2 |
| 3 | dave | 600 | 2 |
+----+------+-------+----------+
output table
+------+----------+----------+
| sent | received | order_id |
+------+----------+----------+
| 300 | 400 | 1 |
| 300 | 1100 | 2 |
+------+----------+----------+
I tried the following with no joy. This does not impose any restrictions on how I would desire to solve this problem. It is just how I attempted to do it.
SELECT *
FROM
( select SUM(value) as sent, order_id FROM sent_table WHERE name='dave' GROUP BY order_id) A
CROSS JOIN
( select SUM(value) as received, order_id FROM received_table WHERE name='dave' GROUP BY order_id) B
Any help would be greatly appreciated.
Do the sums on each table, grouping by order_id, then join the results. To get the rows even if one side is missing, do a FULL OUTER JOIN:
SELECT COALESCE(s.order_id, r.order_id) AS order_id, s.sent, r.received
FROM (
SELECT order_id, SUM(value) AS sent
FROM sent
GROUP BY order_id
) s
FULL OUTER JOIN (
SELECT order_id, SUM(value) AS received
FROM received
GROUP BY order_id
) r
USING (order_id)
ORDER BY 1
Result:
| order_id | sent | received |
| -------- | ---- | -------- |
| 1 | 300 | 400 |
| 2 | | 1100 |
Note the COALESCE on the order_id, so that if it's missing from sent it will be taken from recevied, so that that value will never be NULL.
If you want to have 0 in place of NULL (when e.g. there is no record for that order_id in either sent or received), you would do COALESCE(s.sent, 0) AS sent, COALESCE(r.received, 0) AS received.
https://www.db-fiddle.com/f/nq3xYrcys16eUrBRHT6xLL/2
I have two tables in postgresql looks something like below. please help me with the query to insert into table 1uid column based on column name2.
table 1 table 2
|uid|name1| |uid|name2|table 1uid|
| 1 | a | | 1 | b | |
| 2 | b | | 2 | C | |
| 3 | c | | 3 | a | |
The keyword you need to look for is Update (which changes existing rows). Insert is for creating brand new rows.
But for your particular case, something along the lines of:
update table2 set table1uid = (select uid from table1 where table1.name1 = table2.name2)
I have a table that looks like
+-------+-----------+
| value | timestamp |
+-------+-----------+
and I'm trying to build a query that gives a result like
+-------+-----------+------------+------------------------+
| value | timestamp | MAX(value) | timestamp of max value |
+-------+-----------+------------+------------------------+
so that the result looks like
+---+----------+---+----------+
| 1 | 1.2.1001 | 3 | 1.1.1000 |
| 2 | 5.5.1021 | 3 | 1.1.1000 |
| 3 | 1.1.1000 | 3 | 1.1.1000 |
+---+----------+---+----------+
but I got stuck on joining the column with the corresponding timestamps.
Any hints or suggestions?
Thanks in advance!
For further information (if that helps):
In the real project the max-values are grouped by month and day (with group by clause, which works btw), but somehow I got stuck on joining the timestamps for max-values.
EDIT
Cross joins are a good idea, but I want to have them grouped by month e.g.:
+---+----------+---+----------+
| 1 | 1.1.1101 | 6 | 1.1.1300 |
| 2 | 2.6.1021 | 5 | 5.6.1000 |
| 3 | 1.1.1200 | 6 | 1.1.1300 |
| 4 | 1.1.1040 | 6 | 1.1.1300 |
| 5 | 5.6.1000 | 5 | 5.6.1000 |
| 6 | 1.1.1300 | 6 | 1.1.1300 |
+---+----------+---+----------+
EDIT 2
I've added a fiddle for some sample data and and example of the current query.
http://sqlfiddle.com/#!1/efa42/1
How to add the corresponding timestamp to the maximum?
Try a cross join with two sub queries, the first one selects all records, the second one gets one row that represents the time_stamp of the max value, <3;"1000-01-01"> for example.
SELECT col_value,col_timestamp,max_col_value, col_timestamp_of_max_value FROM table1
cross join
(
select max(col_value) max_col_value ,col_timestamp col_timestamp_of_max_value from table1
group by col_timestamp
order by max_col_value desc
limit 1
) A --One row that represents the time_stamp of the max value, ie: <3;"1000-01-01">
Use the window cause you use with pg
Select *, max( value ) over (), max( timestamp ) over() from table
That gives you the max values from all values in every row
http://www.postgresql.org/docs/9.1/static/tutorial-window.html