In a Microsoft SQL Server Database I have a lookup table that has the following structure:
Assistants:
EmployeeId, AssistantId
Those two IDs are in a second table:
Employees:
Id, FirstName, LastName
I would like to join the two tables and list each Employee and there assistants, it could be more than one. I have tried the following which I thought would work:
select * from Assistants
join Employees
on Assistants.EmployeeId = Employees.Id AND Assistants.AssistantId = Employees.Id
However it returns nothing, any ideas how I can achieve a listing of each employee and there assistants?
You have to use the employee table twice - once to get the employee and once to get the assistant.
I'm assuming not all employees have assistants, so you should probably use left joins:
SELECT * -- You really should specify the columns names here
FROM Employees As Emp
LEFT JOIN Assistants
ON Emp.Id = Assistants.EmployeeId
LEFT JOIN Employees As Assist -- You should probably find a better name for this alias...
ON Assistants.AssistantId = Assist.Id
That will give you a list of all employees and their assistants.
If, however, you can have multiple level of assistants (i.e. the CTO have an assistant CTO and they have an assistant themselves), you will need a recursive cte.
Off the top of my head. Something like this.
Select E.ID, E.FirstName, E.LastName, TBLA.FirstName, TBLA.LastName
FROM Employees E
LEFT JOIN (
Select E.FirstName, E.LastName, A.AssistantId
from Assistants A
INNER JOIN Employees on A.AssistantId = Employees.ID
) TBLA ON TBLA.AssistantId = E.ID
where TBLA.AssistantId is NOT null
Related
I am getting my face kicked in....
I have a total of 4 tables
1. Business (BusinessID, CustomerID, BusName, Territory)
2. Customer (CustomerID, Name)
3. Sales (BusinessID, CustomerID, Territory, Jan, Feb, Mar, Apr, May, Jun)
4. Performance (this is the table I want the info in)
I've already created the table to have the following columns, BusinessID, CustomerID, BusName, Name, Territory, Jan,Feb,Mar,Apr,May,Jun
Every time I try to insert its not properly joining and I am getting a bunch of errors "multi-part identifier could not be bound"
insert into Performance (BusinessID, CustomerID, BusName, Name, Territory, January2018, February2018, March2018, April2018, May2018, June2018)
select Business.BusinessID, Customer.CustomerID, Business.BusName, Customer.Name, Sales.Territory, Sales.January2018, Sales.February2018, Sales.March2018, Sales.April2018, Sales.May2018, Sales.June2018
from Business A
inner join Customer B ON a.CustomerID = b.CustomerID
inner join Sales C ON b.CustomerID = c.CustomerID;
Due to this error I had to do 3 seperate insert into and that caused a bunch of nulls....
face palm is happening and could use some advice.
Image: enter image description here
Thanks,
VeryNew2SQL
You have used table ALIASES, so you have to use those aliases in you SELECT
A for Business, B for Customer and C for Sales.
Read about ALIASES here.
select A.BusinessID, B.CustomerID, A.BusName, B.Name, C.Territory, C.January2018, C.February2018, C.March2018, C.April2018, C.May2018, C.June2018
from Business A
inner join Customer B ON a.CustomerID = b.CustomerID
inner join Sales C ON b.CustomerID = c.CustomerID;
When you create a table alias in your FROM and JOIN clauses, you need to refer to the aliases in your SELECT statement and not the actual table names.
Alternatively, leave your SELECT statement as it is, and adjust your table names to remove the alias. You'll then need the join conditions to refer to your actual table names, rather than the alias. So for example;
select Business.BusinessID, Customer.CustomerID, Business.BusName, Customer.Name, Sales.Territory, Sales.January2018, Sales.February2018, Sales.March2018, Sales.April2018, Sales.May2018, Sales.June2018
from Business
inner join Customer ON Business.CustomerID = Customer.CustomerID
inner join Sales ON Customer.CustomerID = Sales.CustomerID;
Even just try running the SELECT statement above first to make sure you get the query correct before trying it in your insert.
Need to build a temporary table or a CTE for reporting purposes. Users will be able to select a location and courses from drop-downs.
The tables involved are the Person table that holds all employees and a Common Table Expression that will have the courses selected from drop down.
I need to be able to create a temporary table or a CTE with employee id field from the person table and a course name field from Course CTE.
For example, if courses A, B, C are selected each employee will have three records, one for each Course selected. So employee 1 will have three records in this temporary table or CTE. I'm using SQL Server 2008.
You can use INNER JOIN or UNION queries inside CTE to get values from Multiple Tables. So If you want to get the EMployeeId and CourseName for Each employee, YOu can Join the tables inside the CTE like this
;WITH CTE
AS
(
SELECT
E.EmployeeId,
C.CourseNm
FROM dbo.Employee E
INNER JOIN dbo.Course C
ON E.CourseId = C.CourseId
)
SELECT
*
FROM CTE
if you want to use Temp tables, you can try this
SELECT
E.EmployeeId,
C.CourseNm
INTO #Temp
FROM dbo.Employee E
INNER JOIN dbo.Course C
ON E.CourseId = C.CourseId
SELECT * FROM #Temp
I need to do a sub-query from a table to find all employees working in the same department that is part of the same city, but I'm not getting it.
I have the following tables:
Table departments
DEPARTMENTS
department_id
department_name
location_id
Table locations
LOCATIONS
location_id
street_address
postal_code
city
state_province
country_id
Table employees
EMPLOYEES
employee_id
first_name
last_name
email
phone_number
hire_date
job_id
department_id
My code right now is something like that :
SELECT
firt_name,
department_id,
job_id
FROM employees
WHERE state_province = (SELECT state_province FROM locations
WHERE state_province = 'Sao Paulo');
The problem is that while I want to select state_province from the table locations, I can't select the name, department id and job id from the table employees. How can I select both tables while doing the sub-query ?
Anyway, sorry if I did something wrong in the code, I am new to sub-queries.
You could try doing a join between the two tables instead:
SELECT
e.firt_name,
e.department_id,
e.job_id,
l.* -- replace with columns you really want
FROM employees e
INNER JOIN locations l
ON e.state_province = l.state_province
WHERE
e.state_province = 'Sao Paulo';
I don't know which columns you want to select from locations, but it doesn't really make sense to do a join just for state_province alone, as the employees table already has this column. So I just included location.* as a placeholder which you can replace with the columns you actually want.
Edit:
A join is the way to go here IMO, but if you absolutely need to use a subquery, then you can move your current subquery from the WHERE clause to the SELECT clause:
SELECT
firt_name,
department_id,
job_id,
(SELECT l.state_province FROM locations l
WHERE e.state_province = l.state_province) state_province
FROM employees e;
Note that this will only work if there is one matching province. For this and performance reasons, my join query is probably what you would want to use in practice.
I think in your case, sub-query may not be necessary.
A join table can do the trick.
SELECT e.first_name, e.department_id, e.job_id, l.state_province
FROM employees e
LEFT JOIN departments d ON e.department_id = d.department_id
LEFT JOIN locations l ON d.location_id = l.location_id
WHERE l.state_province = 'Sao Paulo';
I am trying to build hierarchies by nesting queries on the same table in MS SQL Server 2014.
To give an example of what I am trying to achieve:
I have a table 'employees' whith the following columns:
[ID],[First Name],[Last Name],[ReportsTo]
{1},{John},{Doe},{2}
{2},{Mary},{Miller},{NULL}
I am trying to build a statement, where I join the employees table with itself and where I build a hierarchy with the boss on top.
Expected Result:
[Employee],[Boss]
{Miller,Mary},{NULL}
{Doe, John},{Miller,Mary}
I apologize, if this is a stupid question, but I fail to create a working nested query.
Could you please help me with that?
Thank you very much in advance
Based on the intended results, it looks like what you essentially want is a list of employees. So let's start with that:
SELECT LastName, FirstName, ReportsTo FROM Employees
This gives you the list, so you now have the objects you're looking for. But you need to fill out more data. You want to follow ReportsTo and show data from the record to which that points as well. This would be done exactly as it would if the foreign key pointed to a different table. (The only difference from being the same table is that you must use table aliases in the query, since you're including the same table twice.)
So let's start by joining the table:
SELECT e.LastName, e.FirstName, e.ReportsTo
FROM Employees e
LEFT OUTER JOIN Employees b on e.ReportsTo = b.ID
The results should still be the same, but now you have more data to select from. So you can add the new columns to the SELECT clause:
SELECT
e.LastName AS EmployeeLastName,
e.FirstName AS EmployeeFirstName,
b.LastName AS BossLastName,
b.FirstName AS BossFirstName
FROM Employees e
LEFT OUTER JOIN Employees b on e.ReportsTo = b.ID
It's a join like any other, it just happens to be a join to the same table.
I've never worked with a non-normalized database before, so I'll try and explain my problem as best I can. So I have two tables:
The customers table holds all the customers information, and the orders table holds all the orders that they have placed. I haven't listed all the fields in the tables, just the ones that I need. The customer number in both tables is not the primary key, but I'm inner joining on them anyway. So the problem I'm having is that I don't know how to make a query that:
Selects all the customers with their first name, last name, and email, and also show the most recent orderdate, most recent total, and most recent ordertype. I know that I have to use a max() aggregate for the date, but that's as far as I got. Please help a noob out.
You can try:
SELECT FirstName,
LastName,
Email,
OrderDate,
OrderTotal,
OrderType
FROM Customers AS C
INNER JOIN Order AS O
ON O.CustomerNumber = C.CustomerNumber AND
O.OrderDate = (
SELECT MAX (O1.OrderDate)
FROM Order AS O1
WHERE O1.CustomerNumber = C.CustomerNumber)
)
assuming that Orders.OrderDate is unique for each CustomerNumber, does this work for you? if a single CustomerNumber has more than one entry in Order for OrderDate, you'll get each of those rows.
select c.FirstName, c.LastName, c.Email, o.OrderDate, o.OrderTotal, o.OrderType
from Customers c
join
(select CusomterNumber, max(OrderDate) as MostRecentOrderDate
from Orders
group by CustomerNumber
) mro on mro.CustomerNumber=s.CustomerNumber
join Orders o on o.OrderDate=mro.MostRecentOrdeDate and
o.CustomerNumber=mro.CustomerNumber
Try this:
SELECT
Customers.*, Orders.*
FROM
Customers
JOIN
(SELECT
Customer_Number,
MAX(Order_Date) OrderDate
FROM
Orders
GROUP BY
Customer_Number
) as Ord ON Customers.Customer_Number = Ord.Customer_Number
JOIN Order ON Orders.Customer_Number = Ord.Customer_Number
If you are doing this with SQL Server use the query designer and basically all you want to do is do a join since you have two keys that are the same one in Customer Table ->Customer Join on Order->Customer alias the Customer table as C and Orders table as O
so for example
SELECT Customer.*, Orders.*
From Customer c, Orders O INNER JOIN O where C.Customer Number = O.Customer Number
This should be enough to get you started.. if you don't want all the fields then fully qualify the names for example
SELECT C.FirstName, C.LastName, O.OrderDate, O.OrderType FROM Customer C, Orders O
WHERE C.Customer NUmber = O.Customer Number //this is another way of doing a Join when working with the where Clause.