This is my query
$searched = 'SELECT first_name, surname, team, id, time FROM users WHERE first_name LIKE "'.$firstname.'%" AND surname LIKE "'.$surname.'%"'
I need to do an inner join on a table of teams.
Structure is as follows.
id
teamname
slug
I need to get the teamname the join is in the teams.id and users.id.
I just can't seem to get the syntax right.
You need INNER JOIN. Also time is a keyword for MySQL and it's better to escape it. Fields id should be used with table name because they are ambiguous. Finally you are under SQL Injection threat.
SELECT users.first_name, users.surname, users.team, users.id AS users_id, `time`
FROM users
INNER JOIN teams
ON teams.id = users.id
WHERE users.first_name LIKE "'.$firstname.'%" AND users.surname LIKE "'.$surname.'%"
Also, is there any particular reason that the JOIN should be on teams.id and users.id. They are supposed to be different things.
Should you not have either team.id = users.teamid or team.userid = users.id in the where condition? Also in the select you have used "team". I guess it should be "teamname".
The SQL should probably be
SELECT
first_name,
surname,
teamname,
id,
time
FROM
users,
teams
WHERE
first_name LIKE "'.$firstname.'%"
AND surname LIKE "'.$surname.'%"'
AND users.teamid = teams.id
Related
I have 2 SQL tables with the following columns:
"users":
userid, firstname, lastname
"orders":
orderid, userid, orderdate, shippingdate
I've been told I can use a join to achieve what I am looking for, but I don't see how a join would work.
The idea is to select all users from "users" that have NOT placed an order; users that do not have a row in the "orders" table as defined by the userid.
This is all I have so far:
select users.userid, users.firstname, users.lastname, orders.*
from users
join orders on orders.userid = users.userid
But that only returns users who DID place an order. How would I expand upon that to get the users that HAVEN'T placed an order? From what I understand, a join is meant to get MORE information, not the lack thereof.
Some info:
I'm using the latest version of HeidiSQL on Windows 10.
You don't need a join to do this, Do:
select * from users where userid not in (select userid from orders)
You can use LEFT JOIN also:
SELECT * FROM users
LEFT JOIN orders ON users.userid= orders.userid
WHERE orders.users IS NULL
I am presently in a DBS course and I am working on an inline view:
SELECT userId, firstname, lastname, gender
FROM
(SELECT COUNT(dvdId) dvdId, u.userId
FROM userDVD
JOIN users u ON userDVD.userId = u.userId
GROUP BY userId) as T
WHERE gender = 'F';
When I run the Query it returns the error unknown column in field list. If I try to specify
u.firstname, u.lastname, u.gender
I return the same error. Any thoughts?
SELECT T.userId, T.firstname, T.lastname, T.gender
FROM (
SELECT users.userId, users.firstname, users.lastname, users.gender
FROM userDVD
JOIN users ON userDVD.userId = users.userId
WHERE gender = 'F' GROUP BY userId
) as T;
I worked through it and it turns out I didn't realize that because I had to alias my inline view that I needed to specify it in the original select statement. This concept was sadly not covered in my course. I appreciate those who gave helpful tips versus rude comments. So, Thank you Drew and Matt
Drew is right that you have a derived table T, but I'll attempt to add some details which might be useful to you as you are in a course.
you have a derived table T
an outer query (first select)
an inner query (second select in brackets)
the inner query uses a table alias of u for users.
the final columns of the inner query are dvdId which is a count of the dvdIds in userDvd table and userId
Because an outer query is constrained to use the final recordset of the inner query only those 2 columns are available to be selected and seeing they don't include firstname, lastname, or gender you are recieving the error.
If you want to keep your query the same but to use those columns you could join your derived table back to the user table and get the columns you desire. Such as this:
SELECT userId, firstname, lastname, gender
FROM
(SELECT COUNT(dvdId) dvdId, u.userId
FROM userDVD
JOIN users u ON userDVD.userId = u.userId
GROUP BY userId) as T
INNER JOIN users u2
ON t.user_id = u2.user_id
WHERE gender = 'F';
That technique to join back to the original table is great for when you have to optimize an aggregation that is on a large table or look for duplicates or something like that. However in your case you really just need a single query aggregating on all of the columns you want in the result set such as this:
SELECT
u.userId, u.firstname, u.lastname, u.gender, COUNT(d.dvdId) as DVDCount
FROM
userDVD d
JOIN users u
ON d.userId = u.userId
WHERE u.gender = 'F'
GROUP BY
u.userId, u.firstname, u.lastname, u.gender
;
I have two tables, say Users and Interviews. One user can have multiple interview records.
Users
-----
UserID
FirstName
LastName
Interviews
----------
InterviewID
UserID
DateOfInterview
I want to get only the latest interview records. Here's my query
select u.UserID, firstname, lastname, max(DateOfInterview) as latestDOI
from users u
left join interviews i
on u.UserID = i.UserID
GROUP BY u.UserID, firstname, lastname
ORDER BY max(DateOfInterview) DESC
How do I update the query to return the InterviewID as well (i.e. the one which corresponds to max(DateOfInterview))?
Instead of using an aggregate function in your select list, you can use an aggregate subquery in your WHERE clause:
select u.UserID, firstname, lastname, i.InterviewId, DateOfInterview as latestDOI
from users u
left join interviews i
on u.UserID = i.UserID
where i.UserId is null or i.DateOfInterview = (
select max(DateOfInterview)
from interviews i2
where i2.UserId = u.UserId
)
That does suppose that max(DateOfInterview) will be unique per user, but the question has no well-defined answer otherwise. Note that the main query is no longer an aggregate query, so the constraints of such queries do not apply.
There are other ways to approach the problem, and it is worthwhile to look into them because a correlated subquery such as I present can be a performance concern. For example, you could use an inline view to generate a table of the per-user latest interview dates, and use joins to that view to connect users with the ID of their latest interview:
select u.*, im.latestDOI, i2.InterviewId
from
users u
left join (
select UserID, max(DateOfInterview) as latestDOI
from interviews i
group by UserID
) im
on u.UserId = im.UserId
left join interviews i2
on im.UserId = i2.UserId and im.latestDOI = i2.DateOfInterview
There are other alternatives, too, some standard and others DB-specific.
Rewrite to use an OUTER APPLY when grabbing your interview, that way you can use order by rather than MAX
select u.UserID, firstname, lastname, LatestInterviewDetails.ID, LatestInterviewDetails.DateOfInterview as latestDOI
from users u
OUTER APPLY (SELECT TOP 1 Id, DateOfInterview
FROM interviews
WHERE interviews.UserID = u.UserId
ORDER BY interviews.DateOfInterview DESC
) as LatestInterviewDetails
Note: This is providing you are using Microsoft SQL Server
I have a table posts with columns board_id, author_id, message. I have another table users with columns id, name, avatar_url.
I need to write a query to get all of the users that have posted on a given board, with no duplicates. The query should return the full user row (id, name, avatar_url).
I've tried
SELECT DISTINCT users.*, posts.author_id
FROM users
INNER JOIN posts
ON users.id = posts.author_id
WHERE posts.board_id = [desired board ID]
but that's giving me duplicates of each user.
There is also the possibility that my query is correct and I've goofed on something elsewhere...
Here's a simple query that will get you all the rows in users with post activity w/o duplication
SELECT * FROM USERS
WHERE id IN (SELECT author_id FROM posts WHERE board_id = [desired board]
You could also use your basic syntax with a distinct on everything you need distinct, e.g.:
SELECT DISTINCT users.*
FROM users
JOIN posts ON users.id = posts.author_id
WHERE posts.board_id = [desired board ID]
Just group by the user id, like so:
SELECT users.id, MIN(users.name), MIN(users.avatar_url)
FROM users
INNER JOIN posts
ON users.id = posts.author_id
WHERE posts.board_id = [desired board ID]
GROUP BY users.id
SELECT users.id, users.name, users.avatar_url, posts.author_id
FROM users
INNER JOIN posts
ON users.id = posts.author_id
WHERE posts.board_id = [desired board ID] GROUP BY users.id
This will get all found rows and then group them by the userid so each user id will appear just once, hence each user row [who posts on the board] will appear just once.
Yet better is use with annotation not for highlighted after IN, which defense against duplicate values. That's it.
Table 1 :- tbl_contacts
Fields
user_id
contact_id
first_name
last_name
Table 2 :- tbl_phone_details
Fields
contact_id
phone_number
phone_type
Table 3 :- tbl_email_details
Fields
contact_id
email_address
email_type
QUERY -
SELECT
tbl_contacts.*, tbl_email_details.*, tbl_phone_details.*
FROM
tbl_contacts, tbl_email_details,
tbl_phone_details
WHERE
tbl_contacts.user_id = '1'
I want to get first_name, last_name, Phone and Email details of particular user_id. I have used above query but its giving me repeated results and I am having less knowledge on DB queries like JOIN and INNER QUERY.
If anyone has any idea, please kindly help.
OUTPUT NEEDED:-
contact_id, first_name, last_name, phone_number, phone_type, email_address, email_type
(Here email and phone number can have 1 or more values for particular users).
Try like this
If you want to retrieve data for particular ID
SELECT T.contact_id,
T.first_name,
T.last_name,
P.phone_number,
P.phone_type,
E.email_address,
E.email_type
FROM tbl_contacts T LEFT JOIN tbl_phone_details P ON
T.contact_id = P.contact_id
LEFT JOIN tbl_email_details E ON
T.contact_id = E.contact_id
WHERE T.contact_id = #contact_id
If you want to retrieve all data
SELECT T.contact_id,
T.first_name,
T.last_name,
P.phone_number,
P.phone_type,
E.email_address,
E.email_type
FROM tbl_contacts T LEFT JOIN tbl_phone_details P ON
T.contact_id = P.contact_id
LEFT JOIN tbl_email_details E ON
T.contact_id = E.contact_id
SELECT tbl_contacts.*, tbl_email_details.*, tbl_phone_details.* FROM
tbl_contacts, tbl_email_details, tbl_phone_details WHERE
tbl_contacts.user_id = '1'
You forgot to mention the condition by which you are going to join all the tables!
SELECT c.first_name, c.last_name, p.phone_number, e.email_address
FROM tbl_contacts c, tbl_email_details e, tbl_phone_details p
WHERE tbl_contacts.user_id = '1'
AND c.contact_id = e.contact_id
AND e.contact_id = p.contact_id;
SELECT c.contact_id, c.first_name, c.last_name,
phone.phone_number, phone.phone_type,
email.email_address, email.email_type
FROM tbl_contacts c
LEFT JOIN tbl_email_details email ON c.contact_id = email.contact_id
LEFT JOIN tbl_phone_details phone ON c.contact_id = phone.contact_id
WHERE tbl_contacts.user_id = '1'
Sql queries are easy to learn and write and they are very useful in getting the important data from database. Joins are used to basically fetch the data from two or more tables on the bases of common column in both tables.
Inner Join will select those values that are common in both of the tables.
Left Join will select all the data from the left table and Right Join will select all the data from right table on the basis of id.
These are the basics of SQL and you must know how to fetch accurate data using them.
this is how I would make that request with JOIN ... but there might be some better or faster way to do it.
SELECT first_name, last_name, phone_number, email_address
FROM tbl_contacts
JOIN tbl_phone_details
ON tbl_contacts.contact_id=tbl_phone_details.contact_id
JOIN tbl_email_details
ON tbl_email_details.contact_id=tbl_contacts.contact_id
WHERE tbl_contacts.user_id = '1';
And just so you don't get lost in all the different answers here (which are probably all correct):
you don't need to give an aliase name to your tables (it's just for readability)
you don't need to mention the table names in your column list if the column name is unique (e.g first_name is only in tbl_contacts). Just if you want the contact_id then you should decide which one (e.g. tbl_phone_details.contact_id)
the multi-select as Jayaram proposed, is exactly the same as the JOIN. MySQL handles both queries the same way (I just didn't see his answer when I responded, sorry)