I want to find the rate of negative and zero profits from a column. I tried to do it using aggregate and subquery but it doesn't seem to work as both method return 0 values.
The code is as follows
SELECT
COUNT(CASE WHEN profit < 0 THEN 1
END) AS negative_profits,
COUNT(CASE WHEN profit < 0 THEN 1
END) / COUNT(profit),
COUNT(CASE WHEN profit = 0 THEN 1
END) AS zero_profits,
COUNT(CASE WHEN profit = 0 THEN 1
END) / COUNT(profit)
FROM sales;
SELECT (SELECT COUNT(*)
FROM sales
WHERE profit <= 0)/COUNT(profit) AS n_negative_profit
FROM sales;
Both query return 0 in values
enter image description here
Avoid integer division, which truncates (like Adrian pointed out).
Also, simplify with an aggregate FILTER expression:
SELECT count(*) FILTER (WHERE profit <= 0)::float8
/ count(profit) AS n_negative_profit
FROM sales;
If profit is defined NOT NULL, or to divide by the total count either way, optimize further:
SELECT count(*) FILTER (WHERE profit <= 0)::float8
/ count(*) AS n_negative_profit
FROM sales;
See:
Aggregate columns with additional (distinct) filters
Because you are doing integer division per docs Math operators/functions.
numeric_type / numeric_type → numeric_type
Division (for integral types, division truncates the result towards zero)
So:
select 2/5;
0
You need to make one of the numbers float or numeric:
select 2/5::numeric;
0.40000000000000000000
and to make it cleaner round:
select round(2/5::numeric, 2);
0.40
Related
I have data like:
YEAR_MONTH|AVG_VISITS|WAS_MEMBER
2020-09|10|True
2020-09|5|False
2019-04|2.5|True
2019-04|5|False
I'd like to make it into a table that calculates the percentage of visits membership added:
YEAR_MONTH|VISIT_PERCENT
2020-09|200
2019-04|50
What is the SQL that would let me look between rows for this sort of calculation?
You just need conditional aggregation as follows:
select year_month,
100 * sum(case when WAS_MEMBER = 'True' then avg_visits end) /
sum(case when WAS_MEMBER = 'False' then avg_visits end) as perc_increase
from your_table t
group by year_month
I had this query select
sum(CASE WHEN kpi.average >= temp.average THEN 1 ELSE 0 END) AS recordOrder,
which worked fine, but I had to change it to this
sum(CASE WHEN sum(kpi.averageUse) / sum(kpi.averageTotal) >= temp.average THEN 1 ELSE 0 END) AS recordOrder,
These queries have to get number of rows, where some value (average) is greater than average from TEMP table. But in the second query I have more accurate data (weighted average).
but I am getting error
1111 invalid use of group function
Any ideas how to write SUM in CASE in SUM?
Thanks!
This code is just non-sensical because you have nested sum functions:
sum(CASE WHEN sum(kpi.averageUse) / sum(kpi.averageTotal) >= temp.average THEN 1 ELSE 0 END) AS recordOrder,
Without seeing your larger query, it is not possible to know what you really intend. But I would speculate that you don't want the internal sum()s:
sum(CASE WHEN (skpi.averageUse / kpi.averageTotal) >= temp.average THEN 1 ELSE 0 END) AS recordOrder,
The objective:
Find the percentage of high elevation airports (elevation >= 2000) by
state from the airports table.
In the query, alias the percentage column as
percentage_high_elevation_airports.
Could someone explain why the following 2 SQL statements give different results:
Correct result:
SELECT state,
100.0 * sum(CASE WHEN elevation >= 2000 THEN 1 ELSE 0 END) / count(*) as percentage_high_elevation_airports
FROM airports
GROUP BY state;
sample result:
MS 0.0
MT 100.0
NC 11.1111111111111
ND 10.0
and wrong result:
select
state,
100.0 * (sum(case when elevation >= 2000 then 1 else 0 end)/count(*)) as percentage_high_elevation_airports
from airports
group by 1;
sample result:
MS 0.0
MT 100.0
NC 0.0
ND 0.0
Only difference is the additional placement of () around the sum.
I would write this as:
SELECT state,
AVG(CASE WHEN elevation >= 2000 THEN 100.0 ELSE 0 END) as percentage_high_elevation_airports
FROM airports
GROUP BY state;
The issue is integer arithmetic. Some databases do an integer division and return an integer. So, 1/2 is 0 rather than 0.5. Some databases also apply this to avg() (but even some that do integer division to numeric averages).
I should note that this is database-specific.
Your question is not about another/better solution to your query
but about the wrong results you get with the use of parentheses, right?
Because:
sum(case when elevation >= 2000 then 1 else 0 end)
results to an integer
and count(*) is by definition an integer.
The division between them is an integer division truncating any decimal digits.
So you get 0 instead of 0.5 or 0.05.
To avoid situations like this you can multiply by a real number like you do: 100.0 first and then divide.
Or you could do this:
sum(case when elevation >= 2000 then 1.0 else 0.0 end)
which results in a sum that is a floating point number.
In any case make sure that at least one of the operands of the division is a real number.
Try below - you need to change the placement of your parenthesis
select
state,
(100.0 * sum(case when elevation >= 2000 then 1 else 0 end))/count(*)) as percentage_high_elevation_airports
from airports
group by 1
I have the following query which returns a total dollar amount.
select sum(cast(dollars as dec)) from financials
This includes positive and negative values.
I would like 2 separate things:
How can I just query the positive dollar amounts? ie. I have 3 records, 10 , -5 , 10. result would be 20.
I want an absolute value as a sum. ie. I have 3 records, 10, -5, 10. the result would be 25.
thanks.
FOR 1) Use conditional SUM()
SELECT SUM( CASE WHEN dollars > 0 then dollars ELSE 0 END) as positive_sum,
SUM( CASE WHEN dollars < 0 then dollars ELSE 0 END) as negative_sum
FROM financials
FOR 2) use ABS()
SELECT SUM( ABS( dollars ) )
FROM financials
Please try below queries. Thanks.
1) select sum(cast(dollars as dec))
from financials
where dollars > 0;
2) select sum(cast(abs(dollars) as dec))
from financials;
You have two queries.solutions are as follows
1.
select sum(dollars) from financials
2.
select sum((case when dollars>0 then dollars end))+sum((case when dollars<0 then -1*dollars end)) from financials
In a single table I have 3 columns. First defines a sector, second count and third amount. I need to extract 5 columns of data in the following manner. First column sector. Second and third to contains the values were amount is less than count and third and four to display were amount is more than count in the specific sectors. How should my query look?
Sample Data - 4 row data for sector one.
1,23,44
1,20,15
1,50,45
1,30,20
Result should be
1,100,80,23,44
You can get it done using a GROUP BY and SUM() aggregate function along with CASE statement like
SELECT sector,
SUM(case when count > amount then count else 0 end) as count1,
SUM(case when amount < count then amount else 0 end) as amount1,
SUM(case when count < amount then count else 0 end) as count2,
SUM(case when amount > count then amount else 0 end) as amount2
FROM mytable
GROUP BY sector;