PostgreSQL: ERROR: column “” does not exist - postgresql

I am trying to to select only those actors with rating over 8.5, however the error comes up saying minrating column does not exist. If I remove the where clause then it works but then I get any rating and not those onl
select name, min(rating) as minrating
from actors
where minrating >8.5
group by name

The WHERE clause should be a HAVING clause:
SELECT name, MIN(rating) AS minrating
FROM actors
GROUP BY name
HAVING MIN(rating) > 8.5
Note that the column alias you defined cannot be used on the HAVING clause, so we need to repeat the MIN expression.

Related

syntax error using redshift listagg function

select id, listagg(timestamp,',')
within group (order by timestamp) as timestamp
from activity group by contact_id order by contact_id limit 1;
This is the error I am getting:
syntax error at or near ","
LINE 1: select eloqua_contact_id, listagg(timestamp,',') within grou...
Anything wrong with this query? When i remove the delimiter option i do not get an error and everything returns fine. How do i add commas to separate the list agg column?
I suspect the issue is the column name "timestamp" as that is a data type and reserved word. If you enclose the column name in double quotes it will keep it from being interpreted as a datatype. (best guess)
select id, listagg("timestamp",',')
within group (order by "timestamp") as "timestamp"
from activity group by contact_id order by contact_id limit 1;
Generally not a good idea to name your columns the same as datatypes.

Syntax error when trying to populate column with count of unique values in another column

I'm trying to count the number of unique pool operators for every permit # in a table but am having trouble putting this value in a new column dedicated to that count.
So I have 2 tables: doh_analysis; doh_pools.
Both of these tables have a "permit" column (TEXT), but doh_analysis has about 1000 rows with duplicates in the permit column but occasional unique values in the operator column (TEXT).
I'm trying to fill a column "operator_count" in the table "doh_pools" with a count of unique values in "pooloperator" for each permit #.
So I tried the following code but am getting a syntax error at or near "(":
update doh_pools
set operator_count = select count(distinct doh_analysis.pooloperator)
from doh_analysis
where doh_analysis.permit ilike doh_pools.permit;
When I remove the "select" from before the "count" I get "SQL Error [42803]: ERROR: aggregate functions are not allowed in UPDATE".
I can successfully query a list of distinct permit-pooloperator pairs using:
select distinct permit, pooloperator
from doh_analysis;
And I can query the # of unique pooloperators per permit 1 at a time using:
select count(distinct pooloperator)
from doh_analysis
where permit ilike '52-60-03054';
But I'm struggling to insert a count of unique pairs for each permit # in the operatorcount column.
Is there a way to do this?
There is certainly a better way of doing this but I accomplished my goal by creating 2 intermediary tables and the updating the target table with values from the 2nd intermediate table like so:
select distinct permit, pooloperator
into doh_pairs
from doh_analysis;
select permit, count(distinct pooloperator)
into doh_temp
from doh_pairs
group by permit;
select count(distinct permit)
from doh_temp;
update doh_pools
set operator_count = doh_temp.count
from doh_temp
where doh_pools.permit ilike doh_temp.permit
and doh_pools.permit is not NULL
returning count;

group by date aggregate function in postgresql

I'm getting an error running this query
SELECT date(updated_at), count(updated_at) as total_count
FROM "persons"
WHERE ("persons"."updated_at" BETWEEN '2012-10-17 00:00:00.000000' AND '2012-11-07 12:25:04.082224')
GROUP BY date(updated_at)
ORDER BY persons.updated_at DESC
I get the error ERROR: column "persons.updated_at" must appear in the GROUP BY clause or be used in an aggregate function LINE 5: ORDER BY persons.updated_at DESC
This works if I remove the date( function from the group by call, however I'm using the date function because i want to group by date, not datetime
any ideas
At the moment it is unclear what you want Postgres to return. You say it should order by persons.updated_at but you do not retrieve that field from the database.
I think, what you want to do is:
SELECT date(updated_at), count(updated_at) as total_count
FROM "persons"
WHERE ("persons"."updated_at" BETWEEN '2012-10-17 00:00:00.000000' AND '2012-11-07 12:25:04.082224')
GROUP BY date(updated_at)
ORDER BY count(updated_at) DESC -- this line changed!
Now you are explicitly telling the DB to sort by the resulting value from the COUNT-aggregate. You could also use: ORDER BY 2 DESC, effectively telling the database to sort by the second column in the resultset. However I highly prefer explicitly stating the column for clarity.
Note that I'm currently unable to test this query, but I do think this should work.
the problem is that, because you are grouping by date(updated_at), the value for updated_at may not be unique, different values of updated_at can return the same value for date(updated_at). You need to tell the database which of the possible values it should use, or alternately use the value returned by the group by, probably one of
SELECT date(updated_at) FROM persons GROUP BY date(updated_at)
ORDER BY date(updated_at)
or
SELECT date(updated_at) FROM persons GROUP BY date(updated_at)
ORDER BY min(updated_at)

Proper GROUP BY syntax

I'm fairly proficient in mySQL and MSSQL, but I'm just getting started with postgres. I'm sure this is a simple issue, so to be brief:
SQL error:
ERROR: column "incidents.open_date" must appear in the GROUP BY clause or be used in an aggregate function
In statement:
SELECT date(open_date), COUNT(*)
FROM incidents
GROUP BY 1
ORDER BY open_date
The type for open_date is timestamp with time zone, and I get the same results if I use GROUP BY date(open_date).
I've tried going over the postgres docs and some examples online, but everything seems to indicate that this should be valid.
The problem is with the unadorned open_date in the ORDER BY clause.
This should do it:
SELECT date(open_date), COUNT(*)
FROM incidents
GROUP BY date(open_date)
ORDER BY date(open_date);
This would also work (though I prefer not to use integers to refer to columns for maintenance reasons):
SELECT date(open_date), COUNT(*)
FROM incidents
GROUP BY 1
ORDER BY 1;
"open_date" is not in your select list, "date(open_date)" is.
Either of these will work:
order by date(open_date)
order by 1
You can also name your columns in the select statement, and then refer to that alias:
select date(open_date) "alias" ... order by alias
Some databases require the keyword, AS, before the alias in your select.

hive Expression Not In Group By Key

I create a table in HIVE.
It has the following columns:
id bigint, rank bigint, date string
I want to get avg(rank) per month. I can use this command. It works.
select a.lens_id, avg(a.rank)
from tableA a
group by a.lens_id, year(a.date_saved), month(a.date_saved);
However, I also want to get date information. I use this command:
select a.lens_id, avg(a.rank), a.date_saved
from lensrank_archive a
group by a.lens_id, year(a.date_saved), month(a.date_saved);
It complains: Expression Not In Group By Key
The full error message should be in the format Expression Not In Group By Key [value].
The [value] will tell you what expression needs to be in the Group By.
Just looking at the two queries, I'd say that you need to add a.date_saved explicitly to the Group By.
A walk around is to put the additional field in a collect_set and return the first element of the set. For example
select a.lens_id, avg(a.rank), collect_set(a.date_saved)[0]
from lensrank_archive a
group by a.lens_id, year(a.date_saved), month(a.date_saved);
This is because there is more than one ‘date_saved’ record under your group by. You can turn these ‘date_saved’ records into arrays and output them.