I currently have a database which houses county codes within a state and clients doing business within those counties. Sometimes, several clients will operate within the same counties. I am looking to display each county code and then that county codes associated clients as separate columns. Example would look something like the below:
County Code Client1 Client2 Client3
32 1 2
42 3
43 6 8
44 2 8 5
45 2
As of now, all I have managed to do is display it as two columns with duplicate county codes displaying different lender IDs. However, this is very manual to put it into the above format once I get it into Excel.
Any suggestions on this?
After review, this can be done with a GROUP_CONCAT(). It puts it as a string so modification with Excel will be needed, but it's a simple solution.
SELECT
COUNTY_CODE,
GROUP_CONCAT(DISTINCT CLIENT_ID)
FROM CLIENT_TABLE
WHERE STATE = 'IA'
GROUP BY COUNTY_CODE
ORDER BY COUNTY_CODE;
Related
Here's my situation : I have a table that has large amounts of records, I need to pull out a number of these records for each name in the database, note that TOP will not work for my use case. My end user wants the report formatted in such a way that each user shows up only once, and up to 3 different dates are shown for the user.
Table format
AutoID
Enum
TNum
Date
Comments
1
25
18
2/2/22
2
25
18
1/2/21
Blah
3
18
18
1/2/21
4
18
18
1/2/20
5
25
17
1/2/22
6
25
17
1/2/20
Now the Enum and TNum fields are fk with other tables, I have created a join that pulls the correct information from the other tables. In the end my query provides this output
RecordID
Training
CompletedDate
FirstName
LastName
Location
2821
MaP
1/1/21
David
Simpson
123 Sesame St.
2822
1/2/22
Fuller
MaP
Dough
GHI
David
123 Sesame St.
2825
1/1/20
Simpson
The two "Blank fields" represent information that is pulled and may or may not be needed in some future report.
So to my question : How do I manage to get a report, with this query's pull to look like this:
Place
LastName
FirstName
Training
FirstCuttoff
Secondcutoff
ThirdCutoff
Comments
123 Sesame St.
David
Simpson
MaP
1/1/20
1/1/21
123 Sesame St.
John
Dough
MaP
1/1/22
I was originally planning on joining my query to itself using where clauses. But when I tried that it just added two extra columns of the same date. In addition it is possible that each record is not identical; locations may be different but since the report needs the most recent location and the name of the trainee. In addition, to add more complexity, there are a number of people in the company with effectively the same name as far as the database is concerned, so rejoining on the name is out. I did pull the Enum in my query, I can join on that if needed.
Is there an easier way to do this, or do I need to sort out a multiple self-joining query?
I have a project I am working on where I am going to have to do this. Some of the suggestions I received were to use a Pivot query. It wouldn't work in my case but it might for yours. Here is a good example
Pivot Columns
id points year country
-----------------------------------
1 45 1998 Mexico
2 45 2000 Germany
3 47 2010 Russia
4 45 1970 China
5 49 2010 Austria
I wonder how can I take row results considering only 2 items from country column. For example only records where country is Germany and Mexico. When I try to get results where only 1 country is criterion the thing is easy:
SELECT * FROM List WHERE Country='Mexico';
the result is:
id points year country
-----------------------------------
1 45 1998 Mexico
but when I try to get results where 2 country items are criteria problems start. I tried:
SELECT * FROM List WHERE country='Mexico' AND Country='Germany';
SELECT * FROM List WHERE country='Mexico' AND 'Germany';
SELECT * FROM List WHERE country='Mexico','Germany';
SELECT * FROM List WHERE country='Mexico'AND WHERE country='Germany';
but no desired result:
id points year country
-----------------------------------
1 45 1998 Mexico
2 45 2000 Germany
I understand that maybe I committed logical error because there is no single record where country is Mexico and Germany at same time, and sql maybe understands claim exactly that way, but, how to write correctly in sql language: Give me results for records where countries are Mexico and Germany. Thanks.
You are looking for IN operator
SELECT * FROM List WHERE Country in ('Mexico','Germany');
Just use OR.
So instead of
SELECT * FROM List WHERE country='Mexico' AND Country='Germany';
it would be
SELECT * FROM List WHERE country='Mexico' OR country='Germany';
IN is also a good function to use, especially if you've got multiple values that you want to check against but that's been covered in the other answers.
You need to use or or in, you have been using and and asking mysql to find a row where country is both Mexico and Germany which is not true.
SELECT * FROM List WHERE Country in ('Mexico','Germany');
try this:
SELECT * FROM List WHERE country='Mexico' OR Country='Germany';
SQL is using logic. Natural language is not.
When you say that you want the results for a list of countries you need to specify so. This request corresponds to an logical or. Since the name can be one or the other, both are correct.
SELECT * FROM List WHERE Country = 'Mexico' OR Country = 'Germany'
To prevent further mistakes like these, I recommend that you look up logical operations in the docs (they are very good). MySQL or the PostGres, both should be fine.
Hypothetical database for events happening around the world.
EVENT
event_id | event_name
1 | Great Wall Party
2 | Times Square Dance
3 | Sydney Blowout
PLACE
place_id | place_name
54 | Times Square
55 | Manhattan
56 | New York City
57 | New York State
58 | USA
EVENTPLACE
eventid | placeid
2 | 54
RELATEDPLACES
rel_placeid1 | rel_placeid2
54 | 55
55 | 56
56 | 57
57 | 58
If I display the event, Times Square Dance, I’d like to display all the places that appear up the chain of its associated places via the RELATEDPLACES table (i.e. Times Square, Manhattan, New York City, New York State, USA). Likewise, if I call all events for USA, I’d like the Times Square dance to be listed, given its EVENTPLACE (Times Square) appears at the bottom of the RELATEDPLACES chain of associations starting with USA.
I think I need to create an inner loop within my SQL command so that it keeps performing until there is a break in the chain. So far (using the first of the two above examples) I have:-
SELECT place_nm FROM eventplace
INNER JOIN relatedplaces ON placeid = rel_placeid1
INNER JOIN place ON rel_placeid2 = place_id
[where the loop should begin:
INNER JOIN relatedplaces ON place_id = rel_placeid1
INNER JOIN place ON rel_placeid2 = place_id
end loop]
WHERE eventid = ‘2’;
This is complicated by the fact that I need different table aliases for each loop, which means I can’t state in the opening SELECT statement that I want to be collecting all the place_name data in the same column.
I’m not sure if I what I am trying to achieve is even possible and my current fallback solution is to list all of Times Square’s related places in the RELATEDPLACES table, rather than just the next largest place (Manhattan), but this seemed like the better solution (and would also save database space).
Can anyone suggest the SQL SELECT command I might need to use? Cheers!
Quite an intriguing problem. But the issue is that MySQL currently does not allow for recursive queries. You have two options :
Decided on the level of RelatedEvents upto which you want to dig into, and create a query for the same (using excel or a small C code)
Use a program to generate and execute the queries on the fly; recursively make DB queries from the program. I suggest this is the best option, though requires repeated DB access.
My question about SEARCH query performance.
I've flattened out data into a read-only Person table (MySQL) that exists purely for search. The table has about 20 columns of data (mostly limited text values, dates and booleans and a few columns containing unlimited text).
Person
=============================================================
id First Last DOB etc (20+ columns)...
1 John Doe 05/02/1969
2 Sara Jones 04/02/1982
3 Dave Moore 10/11/1984
Another two tables support the relationship between Person and Activity.
Activity
===================================
id activity
1 hiking
2 skiing
3 snowboarding
4 bird watching
5 etc...
PersonActivity
===================================
id PersonId ActivityId
1 2 1
2 2 3
3 2 10
4 2 16
5 2 34
6 2 37
7 2 38
8 etc…
Search considerations:
Person table has potentially 200-300k+ rows
Each person potentially has 50+ activities
Search may include Activity filter (e.g., select persons with one and/or more activities)
Returned results are displayed with person details and activities as bulleted list
If the Person table is used only for search, I'm wondering if I should add the activities as comma separated values to the Person table instead of joining to the Activity and PersonActivity tables:
Person
===========================================================================
id First Last DOB Activity
2 Sara Jones 04/02/1982 hiking, snowboarding, golf, etc.
Given the search considerations above, would this help or hurt search performance?
Thanks for the input.
Horrible idea. You will lose the ability to use indexes in querying. Do not under any circumstances store data in a comma delimited list if you ever want to search on that column. Realtional database are designed to have good performance with tables joined together. Your database is relatively small and should have no performance issues at all if you index properly.
You may still want to display the results in a comma delimted fashion. I think MYSQL has a function called GROUP_CONCAT for that.
im using SSIS in visual studio 2008 to perform some fuzzy grouping on a customer table.
columns
ID
Name
Email
etc
I have some duplicate customers in the table with the same email address im currently able to use the Fuzzy grouping to identify the duplicates for manual checking.
I also have some records which are almost duplicates but have some extra punctuation.
eg
ID Name Email
1 bob bob.bob#bob.com
2 bob bob.bob#bob.com
3 bob bob..bob#bob.com
7 tom tom#tom.com
9 frog tom#tom..com
currently i can get id 1 and 2 to match but i would want 1, 2 and 3 to match and be grouped on the same key
and 7 and 9 to also match because i want to ignore the double full stops and see it as only one full stop. Also name does not matter, only the email address column is currently important.
any suggestions and help please.
Use a derived column transformation before your fuzzy grouping transformation to remove unwanted characters:
REPLACE([Email], "..", ".")