I have been trying to change all the values in a column. When I do it turns out to take my table and drop all the rows that match my criteria in the where clause.
Example
|_Month_|_Cost_|_Title_|
|___2___|_15.99|_hello_|
|___2___|_32.87|_John__|
|___2___|_32.87|_Neat__|
|___3___|_32.87|_Kelps_|
|___4___|_32.87|_Gulp__|
|___5___|_32.87|_Tried_|
I run this Query
UPDATE tableName SET Month = 'FEB' WHERE Month = 2;
The Change:
|_Month_|_Cost_|_Title_|
|__FEB__|_32.87|_Neat__|
|___3___|_32.87|_Kelps_|
|___4___|_32.87|_Gulp__|
|___5___|_32.87|_Tried_|
What I need:
|_Month_|_Cost_|_Title_|
|__FEB__|_15.99|_hello_|
|__FEB__|_32.87|_John__|
|__FEB__|_32.87|_Neat__|
|___3___|_32.87|_Kelps_|
|___4___|_32.87|_Gulp__|
|___5___|_32.87|_Tried_|
Where am I going wrong?
I have also tried to get the date changed from a timestamp with
SELECT TO_DATE(payment_timestamp, 'Mon") payment_month
from tablename;
but PostgreSQL doesn't recognize the TO_DATE()?? Can someone tell me why?
Related
I have a table with just two columns:
ts::timestamptz (unique),
values::jsonb
I need to find a row with specific ts, but no matter how I cast and convert things around, it just does not work. E.g.
select t.ts::timestamp from table t limit 1 ... returns 2020-03-16 12:46:02
this query
to_timestamp('2020-03-16 12:46:02','YYYY-MM-DD HH24:MI:SS') ... returns 2020-03-16 12:46:02
but query
select * from table t where t.ts::timestamp = to_timestamp('2020-03-16 12:46:02','YYYY-MM-DD HH24:MI:SS')
returns nothing. Now apparently I'm doing a rookie mistake somewhere, but I just can't see it.
In my table I have the following scheme:
id - integer | date - text | name - text | count - integer
I want just to count some actions.
I want put 1 when date = '30-04-2019' not exist yet.
I want put +1 when is row already exist.
My idea is:
UPDATE "call" SET count = (1 + (SELECT count
FROM "call"
WHERE date = '30-04-2019'))
WHERE date = '30-04-2019'
But it is not working when row doesn't exist.
It is possible without some extra triggers, etc...
You can use a writeable CTE to achieve this. Additionally the UPDATE statement can be simplified to a simple set count = count + 1 there is no need for a sub-select.
with updated as (
update "call"
set count = count + 1
where date = '30-04-2019'
returning id
)
insert into "call" (date, count)
select '30-04-2019', 1
where not exists (select *
form updated);
If the update did not find a row, the where not exists condition will be true and the insert will be executed.
Note that the above is not safe for concurrent execution from multiple transactions. If you want to make this safe, create a unique index on the date column. Then use an INSERT ... ON CONFLICT instead:
insert into "call" (date, count)
values ('30-04-2019', 1)
on conflict (date)
do update
set count = "call".count + 1;
Again: the above requires a unique index (or constraint) on the date column.
Unrelated to the immediate problem, but: storing dates in a text column is a really, really bad idea. You should change your table definition and change the data type for the "date" column to date.
So I have a string time column in a table and now I want to change that time to date time type and then query data for selected dates.
Is there a direct way to do so? One way I could think of is
1) add a new column
2) insert values into it with converted date
3) Query using the new column
Here I am stuck with the 2nd step with INSERT so need help with that
ALTER TABLE "nds".”unacast_sample_august_2018"
ADD COLUMN new_date timestamp
-- Need correction in select statement that I don't understand
INSERT INTO "nds".”unacast_sample_august_2018” (new_date)
(SELECT new_date from_iso8601_date(substr(timestamp,1,10))
Could some one help me with correction and if possible a better way of doing it?
Tried other way to do in single step but gives error as Column does not exist new_date
SELECT *
FROM (SELECT from_iso8601_date(substr(timestamp,1,10)) FROM "db_name"."table_name") AS new_date
WHERE new_date > from_iso8601('2018-08-26') limit 10;
AND
SELECT new_date = (SELECT from_iso8601_date(substr(timestamp,1,10)))
FROM "db_name"."table_name"
WHERE new_date > from_iso8601('2018-08-26') limit 10;
Could someone correct these queries?
You don't need those steps, just use USING CAST clause on your ALTER TABLE:
CREATE TABLE foobar (my_timestamp) AS
VALUES ('2018-09-20 00:00:00');
ALTER TABLE foobar
ALTER COLUMN my_timestamp TYPE timestamp USING CAST(my_timestamp AS TIMESTAMP);
If your string timestamps are in a correct format this should be enough.
Solved as follows:
select *
from
(
SELECT from_iso8601_date(substr(timestamp,1,10)) as day,*
FROM "db"."table"
)
WHERE day > date_parse('2018-08-26', '%Y-%m-%d')
limit 10
I have the following code in Postgres
select op.url from identity.legal_entity le
join identity.profile op on le.legal_entity_id =op.legal_entity_id
where op.global_id = '8wyvr9wkd7kpg1n0q4klhkc4g'
which returns 1 row.
Then I try to update the url field with the following:
update identity.profile
set url = 'htpp:sam'
where identity.profile.url in (
select op.url from identity.legal_entity le
join identity.profile op on le.legal_entity_id =op.legal_entity_id
where global_id = '8wyvr9wkd7kpg1n0q4klhkc4g'
);
But the above ends up updating more than 1 row, actually all of the rows of the identity table.
I would assume since the first postgres statement returns one row, only one row at most can be updated, but I am getting the wrong effect where all of the rows are being updated. Why ?? Please help a nubie fix the above update statement.
Instead of using profile.url to identify the row you want to update, use the primary key. That is what it is there for.
So if the primary key column is called id, the statement could be modified to:
UPDATE identity.profile
SET ...
WHERE identity.profile.id IN (SELECT op.id FROM ...);
But you can do this much simpler in PostgreSQL with
UPDATE identity.profile op
SET url = 'htpp:sam'
FROM identity.legal_entity le
WHERE le.legal_entity_id = op.legal_entity_id
AND le.global_id = '8wyvr9wkd7kpg1n0q4klhkc4g';
This is my result set
i am returning this result set on the base of refid using WHERE refid IN.
Over here, i need to apply a logic without any kind of programming (means SQL query only).
if in result set, i am getting period for particular refid then other rows with the same refid must not returned.
for example, 2667105 having period then myid = 612084598 must not get returned in result set.
according to me this can be achieved using CASE but i have no idea how to use it, i mean that i don't know should i use the CASE statement in SELECT statement or WHERE clause...
EDIT:
This is how it suppose to work,
myid = 612084598 is the default row for refid = 2667105 but if specifically wants the refid for period = 6 then it must return all rows except myid = 612084598
but if i am looking for period = 12, for this period no specific refid present in database.. so for this it must return all rows except first one.. means all rows with the refid which is default one..
Not very clear definition of the problem, but try this:
with cte as (
select
*,
first_value(period) over(partition by refid order by myid) as fv
from test
)
select
myid, refid, period
from cte
where period is not null or fv is null
sql fiddle demo