I have the following query:
$sql = "SELECT first, COUNT(FIRST) FROM techs INNER JOIN ros ON techs.id = ros.writtenby GROUP BY ID";
That gives the desired output of:
first
COUNT(FIRST)
Eric
88
John
11
I have no earthly idea how to display this EXACT table onto a PHP/HTML page. I've created tables based off of queries but it's basically just displaying database table data. I have a feeling the INNER JOIN is the root of my issue since it's not an actual table in the database, rather just results from my query. If this isn't apparent enough already I'm very much a beginner at coding in general so be kind. Lol.
From comments:
I don't understand how to call and then display the "count(first)" column of my query results, since "`count(first)" isn't an actual column in either of the tables I am generating the result from.
If only that's your problem, use alias, like:
SELECT first, COUNT(FIRST) AS my_count FROM techs INNER JOIN ros ON techs.id = ros.writtenby GROUP BY ID
Note that above is the query you posted, just with " AS my_count" added.
Related
I have two tables and I want to join them to get the desired output.
Say the 1st table (seat1) is
and the 2nd table (collegestudents) is
The desired output is
I have tried the below code. But it fails to give the desired result.
$rde2=mysqli_query($con, "select * from seat1 s
left JOIN collegestudents c ON c.Roll = s.Roll
");
Any help please.
You want a left join. Your query looks fine, but you would need not to use select *, and instead explictly list the columns that you want to select, using table prefixes. Otherwise, since you have a Roll column in both tables, a name clashes will happen, that your application apparently does not handle well.
select
s.Roll,
c.Name,
s.Subject
from seat1 s
left join collegestudents c on c.Roll = s.Roll
I am trying to select everything from multiple tables where there are 2 conditions.
But they only bring back a single result from the second table, instead of everything
Here is the MySql code
SELECT *
FROM `core_users`.`users`
LEFT JOIN `core`.`orders`
ON `core_users`.`users`.`uid` = `core`.`orders`.`uid`
LEFT JOIN `core_users`.`crm`
ON `core_users`.`users`.`uid` = `core_users`.`crm`.`uid`
WHERE (`core_users`.`users`.`signup_timestamp` BETWEEN '1476626400' AND '1476712800'
OR (`core_users`.`crm`.`type` = 'refresh_5in5' AND `core_users`.`crm`.`value` BETWEEN '1476626400' AND '1476712800') )
This just brings back 1 result from the crm table. However I want it to bring back all the results from the crm table.
How do I bring back everything from users, orders, and crm while having a WHERE clause on both tables?
Try select users.*, orders.*, crm.*
Please note that, in such case if you have common columns in any of these table like id in every table it would cause an ambiguous column name error. To get rid of that you need to specify these with alias name users.id as user_id, orders.id as order_id, crm.id as crm_id and so on.
I'm trying to write a simple interface for a list of companies using MySQL and PHP. So, I want to fetch some information from my database.
Here are my tables:
companies_data - only for system information.
corporate_data - here I want to keep information about big companies.
individual_data - and here I want to keep information about little companies.
So, here is the tables
And here is the query that I've written:
SELECT
a.id,
a.user_id,
a.added,
a.`status`,
a.company_id,
a.company_type,
a.deposit,
a.individual_operations_cache,
a.corporate_operations_cache,
a.physical_operations_cache,
b.full_name,
b.tax_number,
b.address,
b.statement_date,
b.psrn,
c.full_name,
c.tax_number,
c.address,
c.statement_date,
c.psrn
FROM
companies_data a
LEFT OUTER JOIN corporate_data b
ON (a.company_id = b.id) AND a.company_type = 0
LEFT OUTER JOIN individual_data c
ON (a.company_id = c.id) AND a.company_type = 1
WHERE
a.user_id = 3
This is just the code for a test, I'll expand it soon.
As you see, I've got result with extra fields like %field_name%1, %another_field_name%1 and so on. Of course it is not the mysql error - what I've asked that I've got - but I want to remove this fields? It's possible or I must convert this output on the application side?
thos %field_name%1, %another_field_name%1 , are visible since you are selecting them in your query:
b.full_name,
b.tax_number,
b.address,
b.statement_date,
b.psrn,
c.full_name,
c.tax_number,
c.address,
c.statement_date,
c.psrn
When you use fields with the same name in distinct tables, then the result column name come with this identifier field1, field2, fieldn... in order to distinguish from which table does the field come from.
If you want to avoid this names, you can use aliases as follows:
[...]
b.full_name as corporate_full_name,
[...]
Probably, if every common fields are coincident, you won´t need to show them all, so just remove them from the select.
Hope being usefull for you.
Br.
I'm having trouble with a join query, my issue is as follows.
Table: battles
Fields: id,attacker_id,defender_id
Table: users
Fields: id,profile_image
I would like to do a query to retrieve a battle and get the profile images as well from the other table.
Is there a way to do this in a single or do I have to do more than one?
Thanks in advance.
I wanted to wait a while to see if you had any attempt or if you will answer my first question to know if I understood the problem. But maybe you don't have a starting point. Try something like:
SELECT
a.profile_image as attacker_profile_image,
d.profile_image as defender_profile_image
FROM
`battles` b
LEFT JOIN
`users` a
ON
b.`attacker_id` = a.`id`
LEFT JOIN
`users` d
ON
b.`defender_id` = d.`id`
the problem here is the fact that you need to join with the users table twice, so you will need to create aliases for the columns you plan to use
This query will fetch the two images only, you will need to add the extra fields
I've a ('courses') table that has a HABTM relationship with ('instructors') table through another table...
I want to get the data of an instructor with all related courses in one query..
Currently, I have the following SQL:
SELECT *
FROM `instructors` AS `instructor`
LEFT JOIN `courses` AS `course`
ON `course`.`id` IN (
SELECT `course_id`
FROM `course_instructors`
WHERE `course_instructors`.`instructor_id` = `instructor`.`id`
)
WHERE `instructor`.`id` = 1
This SQL does what it should be doing, the only "problem" I have is that I get multiple rows for each joined rows.
My question is:
Can I get the result I want in one query? Or do I have to manipulate the data in PHP?
I'm using PHP and MySQL.
Each record of a query result set has the same format: same number of fields, same fields, same order of fields. You cannot change that.
SELECT *
FROM instructors AS instructor
LEFT JOIN
course_instructors
ON
instructor.id= course_instructors.instructor_id
LEFT JOIN
courses
ON
course_instructors.course_id = course.id
WHERE instructor.id = 1
This assumes the PK of course_instructors is (instructor_id,course_id)
Explanation of query:
First join + WHERE make sure you get the relevant instructor
Second join matches ALL the entries from the course_instructor table that belongs to this instructor. If none found, will return one row with NULL in all fields
Last join matches all relevant courses from the entries found from course_instructor If none would will return one record with NULL in all fields.
Again: important to use the right constraints to avoid duplicate data.
That's the nature of relational databases. You need to get the instructor first and then get the related courses. That's how I would do it and that's how I've been doing it. I'm not sure if there is a "hack" to it.