I want to count the number of rows where a particular field = 'Q1'.
I usually use count(particular_field), but this does not allow me to count only when that field = 'Q1'.
Does the query SUM(particular_field = 'Q1') work for this matter? Or am I able to do count(particular_field = 'Q1')?
you can either do
select count(*)
from table
where particular_field = 'Q1'
or
select sum(case when particular_field ='Q1' then 1 else 0 end)
from table
You should be able to use a CASE statement with your SUM() (See SQL Fiddle)
SELECT SUM(CASE WHEN particular_field = 'Q1' THEN 1 ELSE 0 END) yourCount
FROM yourTable
Or (See SQL Fiddle) - this will give you a list of the count and each field. If you only want the one value, then use a WHERE clause to filter:
select count(*), particular_field
from yourTable
group by particular_field
Related
I've looked over similar questions and I just can't seem to get this right.
I have a table with three columns: ID, Date, and Method. None are unique.
I want to be able to see for any given date, how many rows match a certain pattern on Method.
So, for example, if the table has 100 rows, and 8 of them have the date "01-01-2020" and of those 8, two of them have a method of "A", I would want a return row that says "01-01-2020", "8", "2", and "25%".
My SQL is pretty rudimentary. I have been able to make a query to get me the count of each method by date:
select Date, count(*) from mytable WHERE Method="A" group by Date;
But I haven't been able to figure out how to put together the results that I am needing. Can someone help me out?
You could perform a count over a case expression for that method, and then divide the two counts:
SELECT date,
COUNT(*),
COUNT(CASE method WHEN 'A' THEN 1 END),
COUNT(CASE method WHEN 'A' THEN 1 END) / COUNT(*) * 100
FROM mytable
GROUP BY date
I'm assuming you're interested in all methods rather than just 'A', so you could do the following:
with ptotals as
(
SELECT
thedate,
count(*) as NumRows
FROM
mytable
group by
thedate
)
select
mytable.thedate,
mytable.themethod,
count(*) as method_count,
100 * count(*) / max(ptotals.NumRows) as Pct
from
mytable
inner join
ptotals
on
mytable.thedate = ptotals.thedate
group by
mytable.thedate,
mytable.themethod
You can use AVG() for the ratio/percentage:
SELECT date, COUNT(*),
SUM(CASE WHEN method = 'A' THEN 1 ELSE 0 END),
AVG(CASE WHEN method = 'A' THEN 100.0 ELSE 0 END)
FROM t
GROUP BY date;
I am unable to derive a SQL query for the following table content.
When i tried below query i am getting above said output. Can someone help me to give the required query for it.
select Name, count(Status) from mytable where Status='Open' group by mytable union
select Name, count(Status) from mytable where Status='Cleared' group by mytable
Use case expressions in the select list to do conditional aggregation.
select Name,
count(case when Status = 'Open' then 1 end) as opencnt,
count(case when Status = 'Cleared' then 1 end) as clearedcnt
from mytable
where Status in ('Open', 'Cleared')
group by Name
COUNT() counts non-null values. The case expressions above returns null when the conditions aren't fulfilled.
I have an sql query problem . I don't want to execute three times query for same result.
In my table I have one field req_type which have three parameter ,
either 1, either 2, either 3 .
I want counter based on req_type in one query instead of by executing query 3 times like below
select count(id) as premium FROM tablename where req_type=1
select count(id) as premium1 FROm tablename where req_type=2
select count(id) as premium2 FROm tablename where req_type=3
I am stuck , can anybody help me?
You could use case for such type of count
select sum(case when req_type=1 then 1 else 0 end) as premium,
sum(case when req_type=2 then 1 else 0 end) as premium1,
sum(case when req_type=3 then 1 else 0 end) as premium2
FROM tablename
Use one query instead of threes by using group by cluase
select req_type , count(id) as premium
FROM tablename
where req_type in (1,2,3)
group by req_type
Use a GROUP BY
SELECT req_type, COUNT(id) AS count_premium
FROM tablename
GROUP BY req_type;
I want to sum up qty*price where type is 'in' and then subtract the sum of qty*price where type is 'out'. Something like this.
SELECT cid, name, SUM(paid_amt), (SELECT SUM(qty*price) WHERE type = 'in' - SELECT SUM(qty*price) WHERE type = 'out'), type FROMtransactionsGROUP BY cid
Here's is my SQL query.
You can solve your problem by using two different sum expressions, each with a slightly different case statement inside of it. The idea is that your case statement only returns a value to the aggregate sum expression if it's of the correct typing.
select
cid
, sum(case when type = "in" then qty*price else 0 end)
- sum(case when type = "out" then qty*price else 0 end)
from
your_table
group by
cid
Assume a simple case e.g. a table bug that has a column status that can be open,fixed etc.
If I want to know how many bugs are open I simply do:
select count(*) as open_bugs from bugs where status = 'open';
If I want to know how many bugs are open I simply do:
select count(*) as closed_bugs from bugs where status = 'closed';
If what want to know how many open and how many closed there are in a query that returns the results in 2 columns i.e.
Open | Closed|
60 180
What is the best way to do it? UNION concatenates the results so it is not what I want
This can be done by using a CASE expression with your aggregate function. This will convert the rows into columns:
select
sum(case when status = 'open' then 1 else 0 end) open_bugs,
sum(case when status = 'closed' then 1 else 0 end) closed_bugs
from bugs
This could also be written using your original queries:
select
max(case when status = 'open' then total end) open_bugs,
max(case when status = 'closed' then total end) closed_bugs
from
(
select status, count(*) as total from bugs where status = 'open' group by status
union all
select status, count(*) as total from bugs where status = 'closed' group by status
) d
Besides the CASE variants that aggregate over the whole table, there is another way. To use the queries you have and put them inside another SELECT:
SELECT
( SELECT COUNT(*) FROM bugs WHERE status = 'open') AS open_bugs,
( SELECT COUNT(*) FROM bugs WHERE status = 'closed') AS closed_bugs
FROM dual -- this line is optional
;
It has the advantage that you can wrap counts from different tables or joins in a single query.
There may also be differences in efficiency (worse or better). Test with your tables and indexes.
You can also use GROUP BY to get all the counts in separate rows (like the UNION you mention) and then use another aggregation to pivot the results in one row:
SELECT
MIN(CASE WHEN status = 'open' THEN cnt END) AS open_bugs,
MIN(CASE WHEN status = 'closed' THEN cnt END) AS closed_bugs
FROM
( SELECT status, COUNT(*) AS cnt
FROM bugs
WHERE status IN ('open', 'closed')
GROUP BY status
) AS g
Try this
select count(case when status = 'open' then 1 end) open_bugs,
count(case when status = 'closed' then 1 end) closed_bugs
from bugs