I have 3 tables:
tbl_Image from which a list of all images will be obtained
A user table from which User ID will be obtained
and an association table of Image and Member called tbl_MemberAssociation.
My work flow is that a user can upload image and this will be stored in to image table. Then all users can view this image and select one of three choice provided along with the image. If user selects an option it will be added to Association table. No user can watch same image more than once. So multiple entries will not be there.
Now I want to find the % of match by getting the list of members choose the same option and different option corresponding to all common images for which they have provided their option.
I.e. say if 3 users say A, B and C view an image of tajmahal. If A and B opted beautiful as choice and C as "Not Good ". For another image say Indian Flag A B and C opted same as Salute. Then for User A: B have 100 % match (since they selected same option both times). For A : C have 50% match one among 2 same.
So this is my scenario, in which I have to find all matched corresponding to currently logged in User.
Please help me.... I am totally disturbed with this procedure.
I have made some assumptions about the actual structure of your tables, but if I understand what you are looking for then I think this query will get the results you are wanting. You may have to make a few modifications to match your table structures.
SELECT
matches.UserName,
CAST(matches.SameRatings AS FLOAT) / CAST(ratings.UserRatingCount AS FLOAT) AS MatchPercent
FROM
tbl_User
CROSS APPLY
(
SELECT
COUNT(*) UserRatingCount
FROM
tbl_MemberAssociation
WHERE
UserId = tbl_User.UserId
) ratings
CROSS APPLY
(
SELECT
u1.UserId,
u1.UserName,
COUNT(*) AS SameRatings
FROM
tbl_MemberAssociation ma
INNER JOIN
tbl_MemberAssociation ma1
ON
ma.ImageId = ma1.ImageId
AND ma.Rating = ma1.Rating
AND ma.UserId <> ma1.UserId
INNER JOIN
tbl_User u1
ON
ma1.userId = u1.UserId
WHERE
ma.UserId = tbl_User.UserId
GROUP BY
u1.UserId,
u1.UserName
) matches
WHERE
tbl_User.UserId = #UserId
ORDER BY
MatchPercent DESC
#UserId could be passed as an input to the stored procedure.
The 1st CROSS APPLY "ratings" is getting a count of for the total number of ratings for the logged in user.
The 2nd CROSS APPLY "matches" is getting a count of the number of like ratings for the other users in the database.
The result set uses the counts calculated by the two CROSS APPLY queries to compute the match percentage between the logged in user and the other users who have rated the same images as the logged in user.
Related
I have this query
SELECT
c.* ,concat ( s.FirstName,'',s.LastName) as FullName
FROM [dbo].[Monitor] c
left join acc.Staff s on s.Id = c.UserId where c.UserId=1
Results:
enter image description here
How to get account information based on last login time in SQL Server.
I don't know how to get account information based on last login time.
From what I understand you want to query the very last login.
SELECT TOP 1 * FROM Monitor m Join Staff s on s.Id = m.UserId
WHERE Object = 'Login' ORDER BY AccessDate Desc
Here is an explanation of the code.
SELECT TOP 1 * FROM Monitor m
The code above is going to query only 1 result (TOP 1) and show all the columns (*) from the table Monitor. If you wish to get only specific columns, you can change * to whatever columns needed. I've given the table Monitor the alias m, because the word starts with that letter, but you can name your alias however you please, for as long as you remember it, or it's easy to realize what column it refers to.
Join Staff s ON s.Id = m.UserID
I've used Join, because you haven't really specified what exact result you are expecting, your question is more about getting the last login, so whatever join is used depends on your expectations. The same goes with the columns I've joined the two tables on. I just copied yours, but they would depend on demanded result and obviously if you have a foreign key in any of the tables, then use that key to join them.
WHERE Object = 'Login' ORDER BY AccessDate DESC
This is the important part of the code for your question. By specifying that we only need rows WHERE the column Object has value of 'Login', we are making sure that only Logins, are shown and all the Logouts are excluded. With ORDER BY AccessDate DESC, we are making sure that the biggest date value is at the top. The way dates work in SQL Server, if you compare two dates, the later date is considered bigger, so the last login would be at the very top, and since we have SELECT TOP 1 at the beginning we are making sure that we are going to get only the very last row.
I'm looking for a solution where a query should return:
a) a limited set of rows when there are rows in the lowest joined table
b) all rows if there is no data in the lowest joined table
c) taking into account that it is possible that there is more than 1 such join
Objective:
we are implementing security using data. Rows from the table (MainTable) are filtered on 1 or more columns. These columns have a relationship with other tables (LookupTable). Security is defined on the LookupTable.
Example1: the MainTable contains contact information. One of the columns holds the country code, this column has a relationship with a LookupTable that contains the country codes. The user can only select a country code that exists in the LookupTable. The security admin can then define that a user can only work with contacts of one or more countries. When that user accesses the MainTable he/she will only get the contacts of that limited list of countries.
Example2: the MainTable contains products. One column holds the country of origin code, another column the product group. Security setup can limit the access to the product MainTable of a user to a list of countries AND a list of product groups.
The security setup works by Management-by-Exception, whichs means that the MainTable is filtered when one or more "security filters" are defined but if no security filters are defined then the user will get ALL rows from MainTable. So my query should return a limited number of rows if any security filter is defined but should return all rows if there are no security filters defined.
Current situation:
I have been working on a query for the case of Example2. There are 4 possible scenarios:
No security filters are defined
expected outcome: all rows are returned
Security filter defined only for first LookupTable
expected outcome: only rows matching values between LookupTable1 and security filter are returned
Security filter defined only for second LookupTable
expected outcome: only rows matching values between LookupTable2 and security filter are returned
Security filter defined only for both LookupTables
expected outcome: only rows matching values between LookupTable1 AND LookupTable2 and security filter are returned
The query I have is correct for cases 2,3 and 4 but fails for case 1 where no rows are returned (as per my understanding this is due to the fact that both JOINS return an empty result set).
Background:
The application provides the (power) users with some kind of table designer which means that they can define which columns are linked to a LookupTable and which of these LookupTables can be used for the "security filters".
This means that, potentially, we could have a MainTable with for example 200 columns of which 20 are linked to a LookupTable which are defined as security filter. The queries are stored procedures which are generated when "design" changes are saved.
With the query I have now (working for 3 out 4 cases) the number of scenarios is equal to 2^N where N is the number of LookupTables. If N is 20 the total goes over 1 million.
Security setup is done with Profiles assigned to Users and Filter Sets assigned to Profiles and Filter Set Entries containing the actual values to filter on (if any).
The environment is currently on MS SQL 2017 but will be put into production on SQL on Azure.
Example of the query (but look further below for the link to dbfiddle):
SELECT E.col_pk, E.col_28, E.col_7, E.col_8, E.col_9, E.col_1052
FROM MainTable AS E
LEFT JOIN LookupTable2 AS L28 ON L28.col_pk = E.col_28
JOIN SecUserProfile AS UP28 ON UP28.IdentityUserId = #UserId
JOIN SecProfileFilterSets AS PFS28 ON PFS28.SecProfileId = UP28.SecProfileId
LEFT JOIN SecFilterSetEntry AS SE28 ON SE28.SecFilterSetId = PFS28.SecFilterSetId AND SE28.MdxEntityId = 2 AND SE28.EntityKey = L28.col_pk
LEFT JOIN LookupTable13 AS L1052 ON L1052.col_pk = E.col_1052
JOIN SecUserProfile AS UP1052 ON UP1052.IdentityUserId = #UserId
JOIN SecProfileFilterSets AS PFS1052 ON PFS1052.SecProfileId = UP1052.SecProfileId
LEFT JOIN SecFilterSetEntry AS SE1052 ON SE1052.SecFilterSetId = PFS1052.SecFilterSetId AND SE1052.MdxEntityId = 13 AND SE1052.EntityKey = L1052.col_pk
WHERE
(SE28.SecFilterSetId IS NOT NULL AND SE1052.SecFilterSetId IS NOT NULL)
OR
(
SE28.SecFilterSetId IS NOT NULL AND
NOT EXISTS
(
SELECT TOP 1 NUP1052.Id FROM SecUserProfile AS NUP1052
JOIN SecProfileFilterSets AS NPFS1052 ON NPFS1052.SecProfileId = NUP1052.SecProfileId
JOIN SecFilterSetEntry AS NSE1052 ON NSE1052.SecFilterSetId = NPFS1052.SecFilterSetId AND NSE1052.MdxEntityId = 13
WHERE NUP1052.IdentityUserId = #UserId
)
)
OR
(
NOT EXISTS
(
SELECT TOP 1 NUP28.Id FROM SecUserProfile AS NUP28
JOIN SecProfileFilterSets AS NPFS28 ON NPFS28.SecProfileId = NUP28.SecProfileId
JOIN SecFilterSetEntry AS NSE28 ON NSE28.SecFilterSetId = NPFS28.SecFilterSetId AND NSE28.MdxEntityId = 2
WHERE NUP28.IdentityUserId = #UserId
)
AND SE1052.SecFilterSetId IS NOT NULL
)
OR
(
NOT EXISTS
(
SELECT TOP 1 NUP28.Id FROM SecUserProfile AS NUP28
JOIN SecProfileFilterSets AS NPFS28 ON NPFS28.SecProfileId = NUP28.SecProfileId
JOIN SecFilterSetEntry AS NSE28 ON NSE28.SecFilterSetId = NPFS28.SecFilterSetId AND NSE28.MdxEntityId = 2
WHERE NUP28.IdentityUserId = #UserId
)
AND
NOT EXISTS
(
SELECT TOP 1 NUP1052.Id FROM SecUserProfile AS NUP1052
JOIN SecProfileFilterSets AS NPFS1052 ON NPFS1052.SecProfileId = NUP1052.SecProfileId
JOIN SecFilterSetEntry AS NSE1052 ON NSE1052.SecFilterSetId = NPFS1052.SecFilterSetId AND NSE1052.MdxEntityId = 13
WHERE NUP1052.IdentityUserId = #UserId
)
)
Issue:
I have the following issues but they probably boil down to 1 in the end:
my current query is only 75% correct
even if my current query is correct it cannot be used in production with the potential high(er) number of lookup tables.
performance needs to be taken into account. Just as we don't know the number of columns and lookup tables at design time we don't know how many rows the tables will contain. The main table may hold 500, 50000 or 500000 records.
In the end all this will boil down to the right solution :)
I think this is not the easiest of questions (otherwise I will feel very stupid) and for those willing to take a look I've prepared a sandbox environment on dbfiddle representing the use-case I'm working with. I've setup the query to run 4 times, once for each of the scenarios.
I am trying to do a query on three different tables.
The variable table
The variable table carries information about what "area", "rounds" and
"days" the variable belongs to. The variable table also holds a pk column.
The pk is used to determine which variable a record belongs to.
The area table
The area table carries information about the "name" of the area as well as
the "role" the area belongs to. A user is assigned a role and then has
access to specific areas.
The record table
The record table carries information about the record that was entered. It
contains the "value", "alarmed", and "alarmType" columns. You can search
for a record based on the variable, round and day.
I am trying to query all of the variables in a certain round and day for a user.
I want to display all the variables whether or not there is a record found. Currently I have a query that only returns the variables that have records, but not the ones that don't.
If there is no record then thevalue, alarmed, and alarmType column should be null.
This is the query that I have so far constructed:
SELECT DISTINCT variable.name, area.name AS "areaName", variable.pk, CAST(record.value AS TEXT) AS "value", record.alarmed, record.alarmType
FROM variable, area, record
WHERE variable.round LIKE '%,1,%'
AND variable.day LIKE '%,3,%'
AND variable.readOnly = 0
AND variable.area IN (SELECT pk
FROM area
WHERE role = (SELECT role
FROM user
WHERE userName LIKE 'Leo'))
AND variable.area = area.pk
AND record.value = (SELECT CASE WHEN COUNT() < 1 THEN NULL
ELSE CAST(value AS TEXT) END
FROM record
WHERE round = 1
AND day = "11-14-2018"
AND variable = variable.pk)
ORDER BY variable.area, variable.position ASC;
Currently it returns something like this:
There are a lot more variables and I want to know how to display them even if there are no records.
I think I see what you're trying to do. The key is using joins (specifically OUTER joins) instead of trying to mash all the tables together and then find similarities. There are also LEFT, RIGHT and INNER flavors (read more about these here and here), depending on what you consider the "complete" or "master" data set - the starting point of your query.
Here's how I understand your relationships (let me know if I have this wrong):
record.variable --> variable.pk
variable.area --> area.pk
area.role --> user.role
In your case, you stated that you need all records from the variable table, so I would start with this:
SELECT v.*
FROM variable v;
Then, you might find all the AREA records related to a particular USER. Use an INNER join to find only records that exist on BOTH sides of the join:
SELECT a.*, u.*
FROM area a
INNER JOIN user u -- Define the table to join
ON a.role = u.role -- Which columns contain keys to match on
WHERE u.userName = 'Leo';
The WHERE filter applies to the user table, but because we are ONLY asking for records from the area table that have a match with user, then that limits the results from the area table.
The next step is to join these two extracts together using another INNER join, again, to find the intersection - matches that exist on BOTH sides of the join(s):
SELECT v.*, a.*, u.*
FROM variable v -- New starting point
INNER JOIN area a
ON a.pk = v.area
INNER JOIN user u
ON a.role = u.role
WHERE u.userName = 'Leo';
Now, we find all the records for a certain day by adding WHERE clauses:
SELECT v.*, a.*, u.*
FROM variable v
INNER JOIN area a
ON a.pk = v.area
INNER JOIN user u
ON a.role = u.role
WHERE u.userName = 'Leo'
AND v.round = 1 -- Add filters for "round"
AND v.day = '11-14-2018'; -- and "day" columns
Next, we use a LEFT join to give us all the records from the table on the "left" plus any matches we find on the "right" side (the "record" table) or NULL if no match is made:
SELECT v.name
,a.name as "areaName"
,CAST(r.value as TEXT) as "value"
,r.alarmed
,r.alarmType
FROM variable v
INNER JOIN area a
ON v.area = a.pk
INNER JOIN user u
ON a.role = u.role
LEFT JOIN record r -- LEFT is important here
ON v.pk = r.variable
WHERE u.userName = 'Leo'
AND v.round = 1
AND v.day = '11-14-2018'
ORDER BY v.area, v.position;
The result from INNER joins (variable + area + user) becomes the "left" side of this join, and the record becomes the "right" side. Using the LEFT join declares that we want ALL records from the left, whether they have a match on the right or not.
I don't have a dataset to test this with, so please excuse any errors I've made.
Hopefully, this illustrates how joins would be used to both eliminate rows and add data (columns) the result, without having to make individual queries or resort to sub-queries (using IN or EXISTS).
Well I am designing a domain model and data mapper system for my site. The system has different kind of user domain objects, with the base class for users with child classes for admins, mods and banned users. Every domain object uses data from a table called 'users', while the child classes have an additional table to store admin/mod/banned information. The user type is determined by a column in the table 'users' called 'userlevel', its value is 3 for admins, 2 for mods, 1 for registered users and -1 for banned users.
Now it comes a problem when I work on a members list feature for my site, since the members list is supposed to load all users from the database(with pagination, but lets not worry about this now). The issue is that I want to load the data from both the base user table and additional admin/mod/banned table. As you see, the registered users do not have additional table to store extra data, while for admin/mod/banned users the table is different. Moreover, the columns in these tables are also different.
So How am I supposed to handle this situation using SQL queries? I know I can simply just select from the base user table and then use multiple queries to load additional data if the user level is found to be a given value, but this is a bad idea since it will results in n+1 queries for n admins/mods/banned users, a very expensive trip to database. What else am I supposed to do? Please help.
If you want to query all usertypes with one query you will have to have the columns from all tables in your result-table, several of them filled with null-values.
To get them filled with data use a left-join like this:
SELECT *
FROM userdata u
LEFT OUTER JOIN admindata a
ON ( u.userid = a.userid
AND u.usertype = 3 )
LEFT OUTER JOIN moddata m
ON ( u.userid = m.userid
AND u.usertype = 2 )
LEFT OUTER JOIN banneddata b
ON ( u.userid = b.userid
AND u.usertype = -1 )
WHERE...
You could probably drop the usertype-condition, since there should only be data in one of the joined tables, but you never know...
Then your program-code will have the job to pick the correct columns based on the usertype.
P.S.: Not that select * is only for sake of simplicity, in real code better list all of the column-names...
While is totally fine having this hierarchy in your domain classes, I would suggest changing the approach in your database. Otherwise your queries are going to be very complex and slow.
You can have just another table called e.g. users_additional_info with the mix of the columns that you need for all your user types. Then you can do
SELECT * FROM users
LEFT JOIN users_additional_info ON users.id = users_additional_info.user_id
to get all the information in a single simple query. Believe me or not, this approach will save you a lots of headaches in the future when your tables start to grow or you decide to add another type of user.
I have a group with a one to many relationship with users. (A group can have zero or 1+ users)
I was to write a jpa query that returns a groups if it has not users attached or if it does have users the id matches my id.
For example if I have group 1 contain user 1 and user 2. group 2 containing no users.
If I was user 3 I want to return group 2 only.
If I was user 2 then I want to return group 1 and group 2
Can I do this in JPA? I know about the IS EMPTY part of JPQL so I can get group 2 returned regardless of user. My problem is how to query inside the list.
Any pointers would be good.
Thank for any help
I think I have it. The answer is to left join with the list.
For example
SELECT g FROM Groups g left join fetch g.users u where (g.users IS EMPTY OR (u.id = :id))
Groups is my entity which contains a list of users