I want to sum the duration of multiple selection.
BMPR-00028.mp4 = 7 seconds
SELECT SUM(durata_video_secondi) as durata_video_secondi
from catalog
WHERE file_video in ('BMPR-00028.mp4','BMPR-00028.mp4')
with this query the result is 7 but I want the SUM of values so I want 14 as result.
I try with
SELECT SUM(durata_video_secondi) as durata_video_secondi
from catalog
WHERE file_video ='BMPR-00028.mp4' OR file_video ='BMPR-00028.mp4'
but the result is always 7 because the values are the same. But I need the sum of values so I need 14 as result.
Can you help me?
Thanks
It doesn't matter how many times you reference the same row, the query will only return one row. SQL is declarative; it doesn't iterate through the list of file_video, you're asking it for all the rows which match the list. There's only one row that matches no matter how many times you ask for it.
Instead, you need to turn the values into rows and join against them; this ensures there is one row for every value, even duplicates. You can do this by inserting them into a temp table, or for small numbers of values you can join with a subquery and union all.
select sum(durata_video_secondi)
from catalog c
join (
select 'BMPR-00028.mp4' as file_video
union all
select 'BMPR-00028.mp4' as file_video
) v on c.file_video = v.file_video;
Demonstration.
Related
I have two tables called tc_revenue and tc_rates.
tc_revenue contains :- code, revenue, startDate, endDate
tc_rate contains :- code, tier, payout, startDate, endDate
Now I need to get records where code = 100 and records should be unique..
I have used this query
SELECT *
FROM task_code_rates
LEFT JOIN task_code_revenue ON task_code_revenue.code = task_code_rates.code
WHERE task_code_rates.code = 105;
But I am getting repeated records help me to find the correct solution.
eg:
in this example every record is repeated 2 time
Thanks
Use a group by for whatever field you need unique. For example, if you want one row per code, then:
SELECT * FROM task_code_rates LEFT JOIN task_code_revenue ON task_code_revenue.code = task_code_rates.code
where task_code_rates.code = 105
group by task_code_revenue.code, task_code_revenue.tier
If code admits duplicates in both tables and you perform join only using code, then you will get the cartessian product between all matching rows from one table and all matching rows from the other.
If you have 5 records with code 100 in first table and 2 records with code 100 in second table, you'll get 5 times 2 results, all combinations between matching rows from the left and the right.
Unless you have duplicates inside one (or both) tables, all 10 results will differ in colums coming either from one table, the other or both.
But if you were expecting to get two combined rows and three rows from first table with nulls for second table columns, this will not happen.
This is how joins work, and anyway, how should the database decide which rows to combine if it didn't generate all combinations and let you decide in where clause?
Maybe you need to add more criteria to the ON clause, such as also matching dates?
So i have a mysql table with over 9 million records. They are call records. Each record represents 1 individual call. The columns are as follows:
CUSTOMER
RAW_SECS
TERM_TRUNK
CALL_DATE
There are others but these are the ones I will be using.
So I need to count the total number of calls for a certain week in a certain Term Trunk. I then need to sum up the number of seconds for those calls. Then I need to count the total number of calls that were below 7 seconds. I always do this in 2 queries and combine them but I was wondering if there were ways to do it in one? I'm new to mysql so i'm sure my syntax is horrific but here is what I do...
Query 1:
SELECT CUSTOMER, SUM(RAW_SECS), COUNT(*)
FROM Mytable
WHERE TERM_TRUNK IN ('Mytrunk1', 'Mytrunk2')
GROUP BY CUSTOMER;
Query 2:
SELECT CUSTOMER, COUNT(*)
FROM Mytable2
WHERE TERM_TRUNK IN ('Mytrunk1', 'Mytrunk2') AND RAW_SECS < 7
GROUP BY CUSTOMER;
Is there any way to combine these two queries into one? Or maybe just a better way of doing it? I appreciate all the help!
There are 2 ways of achieving the expected outcome in a single query:
conditional counting: use a case expression or if() function within the count() (or sum()) to count only specific records
use self join: left join the table on itself using the id field of the table and in the join condition filter the alias on the right hand side of the join on calls shorter than 7 seconds
The advantage of the 2nd approach is that you may be able to use indexes to speed it up, while the conditional counting cannot use indexes.
SELECT m1.CUSTOMER, SUM(m1.RAW_SECS), COUNT(m1.customer), count(m2.customer)
FROM Mytable m1
LEFT JOIN Mytable m2 ON m1.id=m2.id and m2.raw_secs<7
WHERE TERM_TRUNK IN ('Mytrunk1', 'Mytrunk2')
GROUP BY CUSTOMER;
I have a table that include 3 fields (among others) that for each of them that is equal to 1 I need the query to return a record.
So, if all 3 fields are equal to 1 the query should give 3 records.
If two fields (any of the three) are equal to 1 the query should return 2 records and so on.
How would a query like that look?
This should do what you need:
SELECT * from table WHERE field1=1
UNION ALL
SELECT * from table WHERE field2=1
UNION ALL
SELECT * from table WHERE field3=1
The logic is that we select the rows we need for each criteria one by one, and then create an union of them. It is true however, that this does not scale nice... Then again, I have never ever faced this requirement "out in the wild"...
Can anyone help me on how could I join two tables without merging the result into single row? Please see below query:
SELECT *
FROM resorderdetails rd
INNER JOIN resinvalidorderdetails ri
ON rd.itemid=ri.srcitemid;
Let say for example I have 1 row in resorderdetails table with field itemid=1 and I have 1 row in resinvalidorderdetails table with field srcitemid=1.
If we will going to execute the above query, it will return a result of single row [merging the data of two tables]
What I want to do is to have two rows as a result. The first row is the record came from resorderdetails and the other row is the record came from resinvalidorderdetails without using UNION ALL or UNION.
How could I do it? Is it possible?
It's not possible, because you wannna have :
SELECT * FROM resorderdetails rd
and
select * from resinvalidorderdetails
There are only joins operations and UNION which you don't want to use, and the JOINS will put together or remove commons ids and UNION will do exactly what you want
Beside to display a query with 2+ tables you need something in common(even the union need same number of columns).
The issue here is suppose if i want to use two queries seperated by UNION, the query is as
$query=(select a.name,a.age,b.country,b.state from a,b where a.aid=b.bid) UNION (select a.name,a.age,c.profession,c.salary from a,c where a.anid=c.cid)
here the result would only show the first query's result , Any way in which i could display the result of 2nd query also down to the result of first query using UNION. Expecting any help on this. Thanks
Are you after
(
select a.name,a.age,b.country,b.state,null as profession,null as salary
from a,b
where a.aid=b.bid
)
UNION
(
select a.name,a.age,null,null,c.profession,c.salary
from a,c
where a.anid=c.cid
)
You will have null in the profession and salary columns from the first query and null in country and state columns in the second query
Try this
$query=(select a.name,a.age,b.country,b.state from a,b where a.aid=b.bid UNION select a.name,a.age,c.profession,c.salary from a,c where a.anid=c.cid)
by the way the fields in both select must be the same datatype
As I understood it a union was to do the same query on two different tables. If you get a result from the first half of the union you will not get the results from the second half.
Basic property of UNION is
Selected columns listed in
corresponding positions of each SELECT
statement should have the same data
type. (For example, the first column
selected by the first statement should
have the same type as the first column
selected by the other statements.)
If the data types of corresponding
SELECT columns do not match, the types
and lengths of the columns in the
UNION result take into account the
values retrieved by all of the SELECT
statements. For example, consider the
following: