I'm using Bugzilla, and I essentially want to SELECT * FROM bugs table in the "bugs" database. However, the "assigned_to" column actually contains integer values (IDs) instead of a string with the user name.
These IDs match primary keys in the "profiles" table (the "userid" column), and the string I want my query to return is actually stored in the "realname" column in that table.
How can I modify this query to capture all columns in "bugs," but perform a lookup on the assigned_to column and return usernames?
SELECT b.*, p.realname FROM bugs b
JOIN profiles p
ON b.assigned_to = p.userid
Related
I'm new to the relational database stuff and Im having a hard time understanding how to write a query to do what I want. I have two tables that have a relationship.
CREATE TABLE DocumentGroups (
id INTEGER PRIMARY KEY AUTOINCREMENT,
comments TEXT,
Username TEXT NOT NULL,
)
CREATE TABLE Documents (
id INTEGER PRIMARY KEY,
documentGroupId INT NOT NULL,
documentTypeId INT NOT NULL,
documentTypeName TEXT NOT NULL,
succesfullyUploaded BIT
)
I would like to query the Documents table and get the record count for each username. Here is the query that I came up with:
SELECT Count(*)
FROM DOCUMENTS
JOIN DocumentGroups ON Documents.documentGroupId=DocumentGroups.id
GROUP BY Username
I currently have 2 entries in the Documents table, 1 from each user. This query prints out:
[{Count(*): 1}, {Count(*): 1}]
This looks correct, but is there anyway for me to get he username associated with each count. Right now there is no way of me knowing which count belongs to each user.
You are almost there. Your query already produces one row per user name (that's your group by clause). All that is left to do is to put that column in the select clause as well:
select dg.username, count(*) cnt
from documents d
join documentgroups dg on d.documentgroupid = dg.id
group by dg.username
Side notes:
table aliases make the queries easier to read and write
in a multi-table query, always qualify all columns with the (alias of) table they belong to
you probably want to alias the result of count(*), so it is easier to consume it from your application
CREATE TABLE student_activestudent AS
(
SELECT *
FROM
student
INNER JOIN
activestudent ON activestudent.studentnumber=student.studentnumber
);
I am expecting a table with 2 columns of studentnumber but I received Duplicate error instead --> Duplicate column name 'studentnumber'
A database table must have unique column names.
When you do select * you will get all columns from all tables and studentnumber exists on both student table and activestudent table. So to solve you problem specify the columns you want instead of *
CREATE TABLE student_activestudent AS
(
SELECT
student.studentnumber,
..Other columns..
FROM
student
INNER JOIN
activestudent ON activestudent.studentnumber=student.studentnumber
);
At the very least, studentnumber is duplicated. In general, I strongly recommend that a view list all the columns explicitly. This protects the view if underlying columns change.
That said, if studentnumber is the only column, then you can do:
CREATE TABLE student_activestudent AS
SELECT *
FROM student s JOIN
activestudent ast
USING (studentnumber);
With using, the * does not repeat the join keys.
You cannot select two tables that have same column's name.
The best way is not to select *
Select by column and if the column is same you can put [as]
Example
SELECT student.studentnumber as stuNumber, activestudent.studentnumber as actstuNumber
My goal is to create a query, macro or any solution that can do the task described below.
Lets say I have an access 2016 table named "student" with 12 records like this:
And then, lets say I have a second table named "matchme" with 4 records like this:
I need to find a way to
=> first, create a query that returns result of "graduation_date" are equal to Date "1/31/2017" from Table "student" .
=> second, from the result returned from first step, create a query that compare "email" from "student" table with "email" from "matchme" table, and return the [matched] record result.
So the desired result would be:
since the email gary#xxx.com and thomas#xxx.com exist in both tables.
How can I create a query like this?
you can download my access file from here: experiment.accdb
Simple:
select * from student
inner join matchme on student.email = matchme.email
where student.graduation_date = '1/31/2017'
Looking to your data sample you need a join on date and name between the two tables
select * from student
inner join matchme on student.graduation_date = matchme.graduation_date
and student.email = matchme.email
where student.graduation_date = '1/31/2017'
I was surprised by the outcome of these two queries. I was expecting same from both. I have two tables that share a common field but there is not a relationship set up. The table (A) has a field EventID varchar(10) and table (B) has a field XXNumber varchar(15).
Values from table B column XXNumber are referenced in table A column EventID. Even though XXNumber can hold 15 chars, none of the 179K rows of data is longer than 10 chars.
So the requirement was:
"To avoid Duplicate table B and table A entries, if the XXNumber is contained in a table A >“Event ID” number, then it should not be counted."
To see how many common records I have I ran this query first - call it query alpha"
SELECT dbo.TableB.XXNumber FROM dbo.TableB WHERE dbo.TableB.XXNumber in
( select distinct dbo.TableA.EventId FROM dbo.TableA )
The result was 5322 rows.
The following query - call it query delta which looks like this:
SELECT DISTINCT dbo.TableB.XXNumber, dbo.TableB.EventId
FROM dbo.TableB INNER JOIN dbo.TableA ON dbo.TableB.XXNumber= dbo.TableB.EventId
haas returned 4308 rows.
Shouldn't the resulting number of rows be the same?
The WHERE ID IN () version will select all rows that match each distinct value in the list (regardless of whether you code DISTINCT indide the inner select or not - that's irrelevant). If a given value appears in the parent table more than once, you'll get multipke rows selected from the parent table for that single value found in the child table.
The INNER JOIN version will select each row from the parent table once for every successful join, so if there are 3 rows in the child table with the value, and 2 in the parent, then there will be 6 rows rows in the result for that value.
To make them "the same", add 'DISTINCT' to your main select.
To explain what you're seeing, we'd need to know more about your actual data.
We are using audit tables for each operational table, which stores the previous value of its operational equivalent plus change date, change type (UPDATE or DELETE) and its own auto incremental Primary Key.
So, for a table Users with columns UserID, Name, Email there would be a table xUsers with columns ID, OpererationType, OperationDate, UserID, Name, Email.
See that the xTable contains every column that its 'parent' does with 3 extra fields. This pattern is repeated for all tables used by our system.
table Users:
UserID int
Name nvarchar
Email nvarchar
table xUsers:
xUserID int
OpererationType int
OperationDate datetime
UserID int
Name nvarchar
Email nvarchar
Now, my question:
If I have a certain UserID, for which there is 2 entries in the xUsers table when the email was changed twice,
how would I construct a query that identifies which columns (can be more than 1) differ between the two rows in the audit table?
If I'm understanding this correctly, you'd like to create a query passing in the UserID as a parameter, which I'll call #UserID for the following example.
This query will select all rows from xUsers joined onto itself where there is a difference in a non-UserID column, using a series of case statements (one per column) to pull out specifically which columns differ.
SELECT *
, CASE
WHEN a.OperationType <> b.OperationType
THEN 1
ELSE 0
END AS OperationTypeDiffers
, CASE
WHEN a.OperationDate <> b.OperationDate
THEN 1
ELSE 0
END AS OperationDateDiffers
FROM xUsers a
JOIN xUsers b
ON a.xUserID < b.xUserID
AND a.UserID = b.UserID
AND (a.OperationType <> b.OperationType
OR a.OperationDate <> b.OperationDate) -- etc.
WHERE a.UserID = #UserID
You can put the rows of xUsers in a temporary table and then make a while cycle to go for each one and compare the results.
OR
You can do some dynamic SQL and use sysobjects and syscolumns tables to compare each result. It would be more dynamic and then it would be easy to implement for other tables.