Getting those records that have a match of all records in another table - tsql

Question

Within the realm of this problem I have 3 entities:
User
Position
License
Then I have two relational (many-to-many) tables:
PositionLicense - this one connects Position with License ie. which licenses are required for a particular position
UserLicense - this one connects User with License ie. which licenses a particular user has. But with an additional complexity: user licenses have validity date range (ValidFrom and ValidTo)
The problem
These are input variables:
UserID that identifiers a particular User
RangeFrom defines the lower date range limit
RangeTo defines the upper date range limit
What I need to get? For a particular user (and date range) I need to get a list of positions that this particular user can work at. The problem is that user must have at least all licenses required by every matching position.
I'm having huge problems writing a SQL query to get this list.
If at all possible I would like to do this using a single SQL query (can have additional CTEs of course). If you can convince me that doing it in several queries would be more efficient I'm willing to listen in.
Some workable data
Copy and runs this script. 3 users, 3 positions, 6 licenses. Mark and John should have a match but not Jane.
create table [User] (
UserID int identity not null
primary key,
Name nvarchar(100) not null
)
go
create table Position (
PositionID int identity not null
primary key,
Name nvarchar(100) not null
)
go
create table License (
LicenseID int identity not null
primary key,
Name nvarchar(100) not null
)
go
create table UserLicense (
UserID int not null
references [User](UserID),
LicenseID int not null
references License(LicenseID),
ValidFrom date not null,
ValidTo date not null,
check (ValidFrom < ValidTo),
primary key (UserID, LicenseID)
)
go
create table PositionLicense (
PositionID int not null
references Position(PositionID),
LicenseID int not null
references License(LicenseID),
primary key (PositionID, LicenseID)
)
go
insert [User] (Name) values ('Mark the mechanic');
insert [User] (Name) values ('John the pilot');
insert [User] (Name) values ('Jane only has arts PhD but not medical.');
insert Position (Name) values ('Mechanic');
insert Position (Name) values ('Pilot');
insert Position (Name) values ('Doctor');
insert License (Name) values ('Mecha');
insert License (Name) values ('Flying');
insert License (Name) values ('Medicine');
insert License (Name) values ('PhD');
insert License (Name) values ('Phycho');
insert License (Name) values ('Arts');
insert PositionLicense (PositionID, LicenseID) values (1, 1);
insert PositionLicense (PositionID, LicenseID) values (2, 2);
insert PositionLicense (PositionID, LicenseID) values (2, 5);
insert PositionLicense (PositionID, LicenseID) values (3, 3);
insert PositionLicense (PositionID, LicenseID) values (3, 4);
insert UserLicense (UserID, LicenseID, ValidFrom, ValidTo) values (1, 1, '20110101', '20120101');
insert UserLicense (UserID, LicenseID, ValidFrom, ValidTo) values (2, 2, '20110101', '20120101');
insert UserLicense (UserID, LicenseID, ValidFrom, ValidTo) values (2, 5, '20110101', '20120101');
insert UserLicense (UserID, LicenseID, ValidFrom, ValidTo) values (3, 4, '20110101', '20120101');
insert UserLicense (UserID, LicenseID, ValidFrom, ValidTo) values (3, 6, '20110101', '20120101');
Resulting solution
I've setup my resulting solution based on accepted answer which provides the most simplified solution to this problem. If you'd like to play with the query just hit edit/clone (whether you're logged in or not). What can be changed:
three variables:
two variable to set date range (#From and #To)
user ID (#User)
you can toggle commented code in the first CTE to switch code between fully overlapping user licenses or partially overlapping ones.

Answer 1

This makes a number of assumptions (ignores presence of time in the datetime columns, assumes fairly obvious primary keys) and skips the joins to pull in user name, position details, and the like. (And you implied that the user had to hold all the licenses for the full period specified, right?)
SELECT pl.PositionId
from PositionLicense pl
left outer join (-- All licenses user has for the entirety (sp?) of the specified date range
select LicenseId
from UserLicense
where UserId = #UserId
and #RangeFrom <= ValidFrom
and #RangeTo >= ValidTo) li
on li.LicenseId = pl.LicenseId
group by pl.PositionId
-- Where all licenses required by position are held by user
having count(pl.LicenseId) = count(li.LicenseId)
No data so I can't debug or test it, but this or something very close to it should do the trick.

Answer 2

Select ...
From User As U
Cross Join Position As P
Where Exists (
Select 1
From PositionLicense As PL1
Join UserLicense As UL1
On UL1.LicenseId = PL1.LicenseId
And UL1.ValidFrom <= #RangeTo
And UL1.ValidTo >= #RangeFrom
Where PL1.PositionId = P.Id
And UL1.UserId = U.Id
Except
Select 1
From PositionLicense As PL2
Left Join UserLicense As UL2
On UL2.LicenseId = PL2.LicenseId
And UL2.ValidFrom <= #RangeTo
And UL2.ValidTo >= #RangeFrom
And UL2.UserId = U.Id
Where PL2.PositionId = P.Id
And UL2.UserId Is Null
)
If the requirement is that you want users and positions that are valid across the entire range, that is trickier:
With Calendar As
(
Select #RangeFrom As [Date]
Union All
Select DateAdd(d, 1, [Date])
From Calendar
Where [Date] <= #RangeTo
)
Select ...
From User As U
Cross Join Position As P
Where Exists (
Select 1
From UserLicense As UL1
Join PositionLicense As PL1
On PL1.LicenseId = UL1.LicenseId
Where UL1.UserId = U.Id
And PL1.PositionId = P.Id
And UL1.ValidFrom <= #RangeTo
And UL1.ValidTo >= #RangeFrom
Except
Select 1
From Calendar As C1
Cross Join User As U1
Cross Join PositionLicense As PL1
Where U1.Id = U.Id
And PL1.PositionId = P.Id
And Not Exists (
Select 1
From UserLicense As UL2
Where UL2.LicenseId = PL1.LicenseId
And UL1.UserId = U1.Id
And C1.Date Between UL2.ValidFrom And UL2.ValidTo
)
)
Option ( MaxRecursion 0 );

Answer 3

Runnable Version Here
WITH PositionRequirements AS (
SELECT p.PositionID, COUNT(*) AS LicenseCt
FROM #Position AS p
INNER JOIN #PositionLicense AS posl
ON posl.PositionID = p.PositionID
GROUP BY p.PositionID
)
,Satisfied AS (
SELECT u.UserID, posl.PositionID, COUNT(*) AS LicenseCt
FROM #User AS u
INNER JOIN #UserLicense AS perl
ON perl.UserID = u.UserID
-- AND #Date BETWEEN perl.ValidFrom AND perl.ValidTo
AND '20110101' BETWEEN perl.ValidFrom AND perl.ValidTo
INNER JOIN #PositionLicense AS posl
ON posl.LicenseID = perl.LicenseID
-- WHERE u.UserID = #UserID -- Not strictly necessary, we can go over all people
GROUP BY u.UserID, posl.PositionID
)
SELECT PositionRequirements.PositionID, Satisfied.UserID
FROM PositionRequirements
INNER JOIN Satisfied
ON Satisfied.PositionID = PositionRequirements.PositionID
AND PositionRequirements.LicenseCt = Satisfied.LicenseCt
You could probably turn this into an inline table-valued function parameterized on effective date.