I have two tables. One is a table of users with a unique id field, and the other is a table of data, with a column that holds the user id of whoever generated that piece of data.
I want to do something like SELECT data,genned_by FROM datatable; but I want to replace the results for genned_by with SELECT username FROM users WHERE id = genned_by
So that the results from the query changes the userid into a username that corresponds with the other table.
I did some research and figured INNER JOIN might be what I'm looking for, but I'm left very unsure of how to use it after reading it. Help?
Try to use
SELECT d.data, u.username FROM database d INNER JOIN user u ON u.id=d.genned_by
Hope it helps you
SELECT datatable.data,users.username
FROM datatable, users
WHERE users.id = datatable.genned_by
Related
I have two tables that I'm trying to join, 'holidays' and 'users'.
Users contains all my user info, the the column 'id' being primary and unique.
Holidays contains a column called 'userid', which corresponds to the id in the user table.
I'm struggling to get the join statement to work... what I'm looking for is the result of the select statement to give me the friendlyname (column 'fname' in user table) instead of giving me the value of userid.
Here's what I'm trying...
SELECT * FROM holidays JOIN users on users.id=holidays.userid WHERE holidays.status = 0
But i'm not getting a correct result - SQL executes without error, but my DGV is filled with tons of erroneous results.
Apologies If I have not used the correct terminology or whatever.
I'm new to the concept of joins.
Here is hopefully a better explanation of what I am after...
Thanks in advance.
You need to select the specific values you want from every table in the JOIN:
SELECT u.fname
FROM holidays h
JOIN users u
ON u.id = h.userid
WHERE h.status = 0
by the alias (FROM users u) you can select column from users table by u.fname
First try to right join to the User table. If you just want the fname then select the column name in the SELECT query, as SELECT * takes more time then SELECT column name.
I have a users table and an edits table (showing who performed changes on their own or someone else's profile).
In the edits table, the editor and editee are listed using their userid, which is the unique id in the users table.
I would like to create the query:
Select users.username (the editee), users.username (the editor) from users
inner join edits on users.id = edits.editee_id
How would I create a subquery to pull the editor's name?
Thanks
You need to join the users table twice.
SELECT whatever,
editor.username AS editor_username,
editee.username AS editee_username
FROM edits
JOIN users AS editor ON edits.editor_id = editor.id
JOIN users AS editee ON edits.editee_id = editee.id
See what's going on? You use the users table twice, and give it a different alias in each use.
I'm writing what is a pretty simple 2-step SQL Query.
I have one table called Users and another called ProfileCharacteristics.
**Users Table:**
UserId [PK]
UserName
**ProfileCharacteristics Table:**
UserId [FK]
.....(other data)
I'm trying to get access to (other data), but I only have the UserName available. So what I'm presently doing is running one SQL Query that matches the UserName to the UserId and stores the UserId value.
Then, I'm pulling all values that match to UserId in ProfileCharacteristics in a separate query. I have a gut feeling that I could combine these two queries into one, but I'm not sure how.
Any pointers?
EDIT: The start of a JOIN?
SELECT * FROM ProfileCharacteristics
INNER JOIN Users
ON ....
What you're looking for is an INNER JOIN:
SELECT pc.*
FROM ProfileCharacteristics pc
JOIN Users u ON pc.UserId = u.UserId
WHERE U.UserName = 'someuser'
A Visual Explanation of SQL Joins
I have a single table that contain columns:
UserID, EmployeeID, BadgeType, HiredDate, TermDate
Now I need to find userID that are with (gbro, qunro, 1utny, ybeiot, 4ybey)
The 3 users (gbro, qunro, 1utny) exist so it is listed with respective its column info.
What if ybeiot, 4ybey does not exist AT ALL but still I want them listed in a separate table still but with a message that PRINTS: User that does not exist: ybeiot;4ybey
Help, been finding way how to do this.
I tried JOIN (all the joins) but it does not result to what I wanted.
Did you look at SQL EXISTS keyword?
put all the users to be searched in a temp table or table variable #userstoSearch
select * from #userstoSearch us left join users u
on us.UserID=u.UserID where u.userID is not null
select us.UserID from #userstoSearch us left join users u
on us.UserID=u.UserID where u.userID is null
for xml path('')
You need two selects. The first will list the existing values and the second lists the not existing values. You should merge these results using the union keyword.
I have a database with customer information, orders, etc. I need to run a query that returns all customers who have not placed an order at all.
Relevant tables: login and orders
Relevant Columns: login.loginID, login.loginFirstName, login.loginLastName, login.loginEmailAddress AND orders.OrderuserID
So essentially - in psuedocode: compare table login, column loginID for matches in the orders table under orders.OrderUserID. If no match exists (as in no orders placed) then output the users First Name, Last Name and Email address.
I have been racking my brain but having some real issues with the language. I'm a big time N00B when it comes to SQL.
Basically it'll look like that:
SELECT l.login_id
FROM login l
LEFT JOIN orders o
ON l.login_id = o.login_id
WHERE o.login_id IS NULL
The key is using LEFT JOIN with WHERE ... IS NULL condition. In other words, you specifically look for the rows in login table that don't have any information 'extended' within orders table.
That's just a general description, but I hope it should be helpful in your process of constructing the big query specific to your case. )
select loginFirstName, loginLastName, loginEmailAddress
from login
where loginID not in
(select distinct OrderuserID from orders)
You can also do it with a left join:
select loginFirstName, loginLastName, loginEmailAddress
from login left join orders on loginID = OrderuserID
where OrderuserID is null
Not sure which will execute faster; give it a try. The first is easier to understand, IMHO.
EDIT: "select distinct" means "return me the set of unique values of the field". So, the subquery in the first SQL returns the set of users (their IDs) who do have orders. If a user has multiple orders, DISTINCT makes sure her ID is returned only once.
This should do it:
select *
from login l
left join orders o on l.loginId = o.OrderuserID
where o.OrderuserID is null
Try:
select login.loginFirstName, login.loginLastName, login.loginEmailAddress
FROM login
LEFT OUTER JOIN orders ON login.loginID = orders.OrderuserID
WHERE orders.OrderuserID IS NULL;
or something like that. I suspect the trick for a newer SQL user is the LEFT OUTER join. Without that specifier, a join will only return rows from the first table IF there are matches in the second. This way you get them all (and then filter out matches with the IS NULL phrase).
Though you should try first yourself and you could search on google first :):) .
Anyways you can use it in this way,
SELECT l.loginFirstName,l.loginLastName,
l.loginEmailAddress FROM login AS l LEFT JOIN orders as o
ON l.loginID = o.OrderuserID where OrderuserID is NULL