In my relational Database and I have 2 tables:
user
id | userName | email | col1 | col2
log
ID | user_id | cl1 | cl2 | cl3
And I want in my admin section to view all the users along with the count of their records.
I am using SQLite3 as my DB
SELECT user_id,username,email,count(link)'count'
FROM log,user
where user_id=user.id group by user_id;
it works fine but doesn't include users having no record in log table please help how can I make it include all the users and show the count value as 0.
Use LEFT OUTER JOIN to include all the rows from user instead of old style of comma separated INNER JOIN
SELECT user.id,username,email,count(link)'count'
FROM user
LEFT OUTER JOIN Log
ON Log.user_id=user.id
group by user.id;
Related
Here is my table in my database:
table1 table2
---------|-------- --------|
UserID |Type UserID |
---------|-------- --------|
user1 |Busy user1 |
user2 |Free user2 |
user3 |Free user3 |
user4 |Busy user4 |
I would like to select all the userID from table1 where the Type=Free. The only correlation from one table to another is that they have the same UserID in both tables.
What I have so far is :
SELECT UserID
FROM Data.Users
INNER JOIN Data.UserType
ON Data.Users.UserID=Data.UserType.UserID
This only gives me back ALL the userID where the UserID from table 1 = UserID from table 2.
I would like to be able to make it also check for the user type. Something like
SELECT Username FROM Data.Users WHERE TABLE2.UserID = TABLE1.UserID AND
TABLE2.UserType = "free"
I'm new to SQL so I don't think I'm Googling the right thing as well
So your query is working you just need to filter it:
SELECT Data.Users.Name
FROM Data.Users
INNER JOIN Data.UserType
ON Data.Users.UserID=Data.UserType.UserID
WHERE Data.UserType.Type = 'Free'
You have to ensure you are first selecting the data that you want, in this case "Type". So that's all we need to be concerned with when selecting information. However, for illustration purposes (and general good etiquette) lets also select the userID, but we'll take this from table1.
So we want to select Type from Table 2, and UserID from table 1, but where UserID is the same on both tables.
To do what we need to do the following:
SELECT two.Type, one.UserID FROM table2 two INNER JOIN table1 one ON two.UserID = one.UserID
This selects the information, from table2 and we assign it the reference two. Then we join table1 and assign the reference one. We can then grab the requested information in the select using the references we assigned, whilst also ensuring the data is joined where the two tables have identical values.
The above example will select all values where the userID's match, and is used for illustration purposes. Then, to narrow it down, all you have to do is specify the WHERE value on top of this. So:
SELECT two.Type, one.UserID FROM table2 two INNER JOIN table1 one ON two.UserID = one.UserID WHERE two.Type = "Free"
I've got two tables, Job and User, and am trying to pull together some records. Job needs to be joined with User, and User to itself. The structure is:
JobID | OwnerID | ClientName
1 | 1 | Corey
-----------------------------
UserID | ManagerID | Name | Email
1 | 2 | Jon Smith | job#test.com
2 | | Jane Doe | jane#test.com
I'm looking to obtain a table that contains the manager's email address, in addition to the user's name. My query is:
SELECT
Job.ClientName as 'ClientName',
U1.Name as 'SalesPersonName',
U2.Email as 'ManagerEmail'
FROM
Job
INNER JOIN User U1 ON Job.OwnerID = U1.UserID
INNER JOIN User U2 ON U1.UserID = U2.ManagerID
WHERE
Job.ID = '1'
This pulls all Job data, and all data for U1...but is failing to populate U2 - the manager's information.
I imagine I've got something messed up with the self-join. The query validates, so I'm at a loss for what it is.
Any guidance is greatly appreciated.
Note: the above table/column names have been simplified to protect the innocent.
It looks like you juxtaposed the table aliases on the fields in your last JOIN:
This: FULL JOIN User U2 ON U1.UserID = U2.ManagerID
Should be this: FULL JOIN User U2 ON U2.UserID = U1.ManagerID
Full query:
SELECT
Job.ClientName as 'ClientName',
U1.Name as 'SalesPersonName',
U2.Email as 'ManagerEmail'
FROM
Job
FULL JOIN User U1 ON Job.OwnerID = U1.UserID
FULL JOIN User U2 ON U2.UserID = U1.ManagerID
WHERE
Job.ID = 1 --removed ticks here, assuming int column
Note: You don't need a FULL JOIN unless there are records that won't join together, and you want to preserve those records with NULL values in your result set. For the example provided, a basic INNER JOIN would work, but maybe you need the FULL JOIN for your true data set so I left it in.
Note 2: user is a reserved word in many DBMS and could cause you headaches if used as a tablename
I'm doing a clone of Twitter using PostgreSQL. The users can write posts and they can share them. There is a timeline for each user, where it shows the posts and the shares of the people he follows. I also have to show the difference between a shared post (retweet) and a regular one by the original author. I have the following problem when joining the tables:
Post
post_id | user_id | text
1 1 text
Shares
post_id | user_id
1 2
Join_result
Post.post_id | Post.user_id | Post.text | Shares.post_id | Shares.user_id
1 1 text 1 2
Then I filter by Post.user_id or Shares.user_id. However, with this result, I don't know if I'm showing the post because it is a user 2 sharing or user 1 post. A good solution to me, it would be this join table:
Join_result
Post.post_id | Post.user_id | Post.text | Shares.post_id | Shares.user_id
1 1 text null null
1 1 text 1 2
Now I could filter correctly:
(Post.user_id in following and Share.user_id is NULL) or Share.user_id in followings
In this example, if the user follows user 1, it returns the first row; if he follows user 2 I get the second one and if he follows the two users, returns the two rows.
I've already solved this problem using a UNION query but I'd like to know if there is another solution (and better).
EDIT the query:
SELECT p0* f1.*, FROM "posts" AS p0
LEFT OUTER JOIN "forwards" AS f1 ON f1."post_id" = p0."id"
INNER JOIN (SELECT id FROM users AS u0
INNER JOIN follows AS f1 ON (f1.follower_id = $1) AND (f1.following_id = u0.id) UNION
SELECT id FROM users AS u1 WHERE (u1.id = $1)
) AS f3 ON (p0."author_id" = f3."id") OR (f1."user_id" = f3."id") ORDER BY p0."inserted_at" DESC
You are using a LEFT OUTER JOIN, in that case if no forward exists it will set null values in the results.
See this post for more information:
What is the difference between "INNER JOIN" and "OUTER JOIN"?
I have tables users and topics. Every user can have from 0 to several topics (one-to-many relationship).
How I can get only those users which have at least one topic?
I need all columns from users (without columns from topics) and without duplicates in table users. In last column I need number of topics.
UPDATED:
Should be like this:
SELECT user.*, count(topic.id)
FROM ad
LEFT JOIN topic ON user.id = topic.ad
GROUP BY user.id
HAVING count(topic.id) > 0;
but it takes 0 result. But it should not be 0.
Firstly you need to have your two tables, because you have left limited information about your table structure I will use an example to explain how this works, you should then be able to easily apply this to your own tables.
Firstly you need to have two tables (which you do)
Table "user"
id | name
1 | Joe Bloggs
2 | Eddy Ready
Table "topic"
topicid | userid | topic
1 | 1 | Breakfast
2 | 1 | Lunch
3 | 1 | Dinner
Now asking for a count against each user is done using the follwing;
SELECT user.name, count(topic.topicid)
FROM user
INNER JOIN topic ON user.id = topic.userid
GROUP BY user.name
If you use a left join, this will include records from the "user" table which does not have any rows in the "topic" table, however if you use an INNER JOIN this will ONLY include users who have a matching value in both tables.
I.e. because the user id "2" (which we use to join) is not listed in the topic table you will not get any results for this user.
Hope that helps!
use inner join and distinct
select distinct user_table.id
from user_table
inner join topics_table on topic_table.user_id = user_table.id
select u.id
, u.name
, count(b.topicName)
from user u
left join topic t on t.userid = u.id
group by u.id, u.name
You can select topic number per user and then join it with user data. Something like this:
with t as
(
select userid, count(*) as n
from topic
group by userid
)
SELECT user.*, t.n
FROM user
JOIN t ON user.id = t.userid
Alright, I'm pretty desperate. This is my first time using StackOverflow (I've always find all my answer but not this time). Please Community I need your help cause I'm not a SQL wiz. (I'm using Access).
I have 3 tables "User", "Type" and "User_update". I want to get the value from the "User" table but if there's an update for that user in the "User_update" table I would like to have the value from the "User_update" table instead and the date of the update. :-/
TABLE "USER"
id | user | type_id
--------------------
0 | bibi | 1
1 | toto | 1
TABLE "TYPE"
id | type
-----------
0 | admin
1 | normal
TABLE "USER_UPDATE"
id | user_id | type_id | date
-----------------------------------
0 | 1 | 0 | 9/3/2015
Would like to get something like this:
user | type | date
--------------------
bibi | normal |
toto | admin | 9/3/2015
Hope you guys can help!
I don't know Access, but here's an ANSI SQL answer:
select coalesce(uu.user, u.user), t.type, uu.date
from user u
left join user_update uu on u.id = uu.id
join type t on t.id = coalesce(uu.type_id, u.type_id)
The LEFT JOIN is there to read from user_update if a matching row is found. COALESCE returns the first non-null value, so if a user_update has been found that value is returned, otherwise user value is returned.
NOTE: In ANSI SQL date and user are reserved words, so these may need to be delimited, e.g. "date" or perhaps [date].
Access attempts:
select coalesce(uu.user, u.user), t.type, uu.date
from (user u
left join user_update uu on (u.id = uu.id))
join type t on (t.id = coalesce(uu.type_id, u.type_id))
Or perhaps:
select coalesce(uu.user, u.user), t.type, uu.date
from type t
join (user u
left join user_update uu on (u.id = uu.id))
on (t.id = coalesce(uu.type_id, u.type_id))
As someone new to access, I would recommend you design most of your queries using the "Design View". You want to left join the USER table on both tables, using the USER.type_id = TYPE.id and USER.user = USER_UPDATE.user
The following SQL should accomplish what you want, returning the "USER_UPDATE" record should it have a value, otherwise it will return the "TYPE" record.
You will need to look to see if there can be multiple records in "USER_UPDATE" for the same user, depending on your use, the return of multiple records may not be what you are looking for, you will need to build a select query to return only the most recent record in "USER_UPDATE"
SELECT USER.id, USER.user, USER.type_id, IIf([USER_UPDATE].[type] Is Null, [type].[type],[USER_UPDATE].[type]) AS user_type, USER_UPDATE.date
FROM ([USER] LEFT JOIN TYPE ON USER.type_id = TYPE.id) LEFT JOIN USER_UPDATE ON USER.user = USER_UPDATE.user;