So if we have two columns 'Domain' and 'Score'. There are duplicate domains with different scores. How would I add all the scores together that are from the same domain?
and furthermore, how do I then show it separately in another table?
Thanks,
Leon.
query look like this.
SELECT Domain, sum(NZ(Score,0)) as total FROM yourtable group by Domain
Related
I have a table in which each record is a single purchase made by a single client.
Purchases can be made in different categories of product and different geographical areas (each of these is a single field).
I can count how many purchases each client has in each combination of product/area like this
Select client_id, product_id, zone_id, COUNT(purchase_id)
Group by client_id, product_id, zone_id
From this I would like to get a table where each record is the client, product and zone with the highest number of purchases. So only one row per client.
How would I go about doing this?
I think I might be able to do it by using NOT EXISTS where there is no record with the same three identifiers and higher COUNT, but as this is part of a much larger query I'm afraid of performance issues.
I also figure I might be able to concatenate the three identifiers into a single one, but I need those identifiers to be in separate fields as I need them for a join in another query this will be part of.
Step 1: Generate a temp table with the 3 columns plus count as you mentioned.
Step 2: Apply a groupwise-max algorithm. Either follow the link you have or check out Groupwise-Max
Below find the sample table.I want to calculate the total population(emp+nemp) of each country.Means i have to add the two columns which can be easily done and then add the data from multiple rows as well as per the same country name.
This the sample table.
Try this
SELECT
T.country,
SUM(T.emp + T.nemp) People
FROM
YourTable T
GROUP BY
T.country
As of right now, creating a query with all records from both tables I want to display gives me every record for table b for the first record of table a, then every record of table b for the second record of table a, and so on.
SELECT *
FROM tblSales, tblRepair;
I want to be able to format these tables so that records from each table are displayed within a report, but separately (not joined). Both these tables contain sales data that need to be displayed and calculated together on a daily basis, but my problem right now is getting the data out of these tables and together in a format that doesn't join each record together.
Thanks in advance.
You can use a UNION query to combine both tables. I've added a dummy column to distinguish between the two tables:
SELECT *,'Sales' AS TheTable FROM tblSales
UNION ALL SELECT *, 'Repairs' FROM tblRepairs;
This will list all the Sales records first, followed by all the Repairs. You can add an ORDER BY clause to change this.
Alternatively, depending on the type of report you are creating, you could base the main report on one table and add a subreport based on the second.
I am a web developer so my knowledge of manipulating mass data is lacking.
A coworker is looking for a solution to our data problems. We have a table of about 400k rows with company names listed.
Whoever designed this didnt realize there needed to be some kind of unique identifier for a company, so there are duplicate entries for company names.
What method would one use in order to match all these records up based on company name, and delete the duplicates based on some kind of criteria (another column)
I was thinking of writing a script to do this in php, but I really have a hard time believing that my script would be able to execute while making comparisons between so many rows. Any advice?
Answer:
Answer origin
1) delete from table1
2) USING table1, table1 as vtable
3) WHERE (NOT table1.ID>vtable.ID)
4) AND (table1.field_name=vtable.field_name)
Here you tell mysql that there is a table1.
Then you tell it that you will use table1 and a virtual table with the values of table1.
This will let mysql not compare a record with itself!
Here you tell it that there shouldn’t be records with the same field_name.
The way I've done this in the past is to write a query that returns only the set I want (usually using DISTINCT + a subquery to determine the right record based on other values), and insert that into a different table. You can then delete the old table and rename the new one to the old name.
To find list of companies with duplicates in your table you can use script like that:
SELECT NAME
FROM companies
GROUP BY NAME
HAVING COUNT(*) > 1
And following will delete all duplicates except containing max values in col column
DELETE del
FROM companies AS del
INNER JOIN (
SELECT NAME, MAX(col) AS col
FROM companies
GROUP BY NAME
HAVING COUNT(*) > 1
) AS sub
ON del.NAME = sub.NAME AND del.col <> sub.col
Here is my case, I have a database table with below fields:
name
place_code
email
phone
address
details
estd
others
and example data
If you look at the above example table, first three records are talking about xyz and place code 1020.
I want to create a single record for these three records based on
substring(name,1,4)
place_code
(I am lucky here for all the similar records satisfies this condition and unique in the table.)
For the other columns which record column length has max. For example again for the above 3 records email should be test#te.com, phone should be 657890 and details should be "testdetails".
This should be done for all the table. (Some has single records and some has max 10 records.)
Any help on query that helps me to get the desired result?
Answer
Some one posted the below answer and deleted it . But that looks a good solution
SELECT max(name),
place_code,
max(email),
max(phone),
max(address),
max(details),
max(estd),
max(others)
FROM table_x
GROUP BY substring(name,1,4),place_code
Please let me know if you guys see any issues in it ?
Thank You all
Kiran
You need the awesome GROUP_CONCAT aggregate function.
SELECT place_code,
substring(name,1,4) name,
GROUP_CONCAT(email),
GROUP_CONCAT(Phone),
GROUP_CONCAT(details)
FROM table
GROUP BY place_code, substring(name,1,4)
It has options allowing you to control things like the order of items in the string and the separators. See http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat
SELECT max(name),
place_code,
max(email),
max(phone),
max(address),
max(details),
max(estd),
max(others)
FROM table_x
GROUP BY substring(name,1,4),place_code