I have two tables in one MySQLI database. One is called 'actions' and one is called 'links'. But recently I have noticed that many links which I have transfered from my old system don't have any actions attached to it, and I want to count how many they are. So I want to count the amount of links whose id hasn't any entries in the actions table. How can I formulate the statement. There is one id in the links table and one link_id in the actions table.
You are looking for a outer join. without a lot of details, it would look something like:
SELECT * FROM links
LEFT JOIN actions on links.field = actions.field
WHERE actions.ID is NULL;
This will give you all the links records that don't have a corresponding record in actions.
Related
I have two sheets in excel. One has CBG (neighborhood) IDs as shown below.
The second sheet has state and county names and IDs as shown below.
Now the first 5 digits in the CBG ID are just the corresponding state and county IDs for that CBG.
I need to to join this data together in Tableau so that I would have the state and county on the CBG sheet for each CBG.
Basically I tried to blend the data and it didn't work. I also tried to perform a join calculation using the 5-digit code in the second sheet and the LEFT function to extract the 5-digits in the CBG code but it didn't seem to work either.
To fix it, just needed to fix the Join calculation on both sides of the join.
Also, it seems that both variables to be joined need to be the same data type.
The data that you analyze in Tableau is often made up of a collection of tables that are related by specific fields (that is, columns). Joining is a method for combining the related data on those common fields. The result of combining data using a join is a virtual table that is typically extended horizontally by adding columns of data.
When joining tables, the fields that you join on must have the same data type. If you change the data type after you join the tables, the join will break.
Please go through the below steps for joining tables:
In Tableau Desktop: on the start page, under Connect, click a connector to connect to your data. This step creates the first connection in the Tableau data source.
In web authoring: Select New Workbook and connect to your data. This step creates the first connection in the Tableau data source.
Select the file, database, or schema, and then double-click or drag a table to the canvas.
Double-click or drag another table to the canvas, and then click the join relationship to add join clauses and select your join type.
Add one or more join clauses by selecting a field from one of the available tables used in the data source, a join operator, and a field from the added table. Inspect the join clause to make sure it reflects how you want to connect the tables.
When you are finished, close the Join dialog.
Thank you.
There are two tables, one for Student and one for Borrowed Books. In the Microsoft Access (2010, 2013), it is easy to display a form Student based on the table Student, and other form BorrowedBooks based on the table Borrowed Books with their Record Source pointed.
How to do Form BorrowedBooks showing records for the current student showing on the Form Student one at one time? I'm looking to learn both VBA script and using the built-in controls to achieve the result.
Relationship between has been built. And it's one student to many books relationship.
One VBA approach like:
DoCmd.OpenForm "BorrowedBooks", , , "StudentID = " & Me.StudentID
The real trick is figuring out which event to put code into.
Another option is to use form/subform arrangement - main form bound to Students table and subform bound to BorrowedBooks. Have you looked at Microsoft Lending Library database template?
so if my understanding of your question is clear then you need to join operation on the tables
SELECT *
FROM
student
INNER JOIN borrowedbooks ON (The two table'S related column ie student.pk=borrowedbooks.fk)
you can also add a where clause if you want from here you can state you primary key in student table and it relationshi
My question is a variation on one already asked and answered (TSQL Delete Using Inner Joins) but I have a different level of complexity and I couldn't see a solution to it.
My requirement is to delete Special Prices which haven't been accessed in 90 days. Special Prices are keyed on Customer ID and Product ID and the products have to matched to a Customer Order Detail table which also contains a Customer ID and a Product ID. I want to write one function that will look at the Special Price table for each Customer, compare each Product for that Customer with the Customer Order Detail table and if the Maximum Order Date is more than 90 days earlier than today, delete it from the Special Price table.
I know I can use a CURSOR (slow but effective) but would prefer to have a single query like the one in the TSQL Delete Using Inner Joins example. Any ideas and/or is more information required?
I cannot dig more on the situation of your system but i think and if it is ok for you, check MERGE STATEMENT, it might be a help instead of using cursors. check this Link MERGE STATEMENT
I'm new to Filemaker and need some advice on auto-populating tables.
Part 1:
I have TableA which includes many records with client information. I want a separate TableB which is identical to TableA except that it is "de-identified"; that is, it does not contain two of the fields, first name and last name.
I would like the two tables to interact such that if I add a new record to TableA, that same record (sans first and last name) appear automatically in TableB.
Part 2:
In addition to the above functionality, I would also like said functionality to be dependent on a specific field type from TableA. For example, I enter a new record, which has a "status" field set to "active," into tableA. I then want that record to be auto-popualted into TableB; however, if I add another record with a "status" of "inactive," I want that that record auto-populated into a TableC but not into TableB.
FileMaker can perform this with script triggers so long as every layout where TableA will be edited has a layout script trigger of OnRecordCommit connected to it. When the record is committed (which can happen in a number of ways), the attached script will run, which you can use to create the appropriate record in the appropriate table.
The script could create the record in a number of ways. If the primary keys for both records are the same, you could use lookups. You could export the record in TableA and then import it into the correct table. You could pass the field information as a parameter to the script. The best choice really depends on your needs.
Having said that, I would question the wisdom of this approach. It brings up a few questions that would seem to complicate matters. For example, what happens when the status changes? When a record in TableA is deleted? When fields in TableA are modified? Each of these contingencies (and others) will require thought and more complicated scripts.
So I would ask what problem you're really trying to solve. My best guess is that you are trying to keep the name information private from certain users. User accounts and privileges with dedicated layouts for each privilege can solve this without the need for duplicate tables. FileMaker privilege sets can be quite granular.
For example, you can specify that users with PrivilegeA can create records and view names, but PrivilegeB users can only view records if the status is "active" and the name fields are not available to them, while PrivilegeC users can view records if the status is "inactive" and the name fields are also not available to them.
I would definitely use filters and permissions on the "status field" to achieve this and not two mirroring tables. Unless the inactive information is drastically different, you would be complicated your solution and creating more possible pitfalls.
I have two tables in APEX that are linked by their primary key. One table (APEX_MAIN) holds the basic metadata of a document in our system and the other (APEX_DATES) holds important dates related to that document's processing.
For my team I have created a contrl panel where they can interact with all of this data. The issue is that right now they alter the information in APEX_MAIN on a page then they alter APEX_DATES on another. I would really like to be able to have these forms on the same page and submit updates to their respective tables & rows with a single submit button. I have set this up currently using two different regions on the same page but I am getting errors both with the initial fetching of the rows (Which ever row is fetched 2nd seems to work but then the page items in the form that was fetched 1st are empty?) and with submitting (It give some error about information in the DB having been altered since the update request was sent). Can anyone help me?
It is a limitation of the built-in Apex forms that you can only have one automated row fetch process per page, unfortunately. You can have more than one form region per page, but you have to code all the fetch and submit processing yourself if you do (not that difficult really, but you need to take care of optimistic locking etc. yourself too).
Splitting one table's form over several regions is perfectly possible, even using the built-in form functionality, because the region itself is just a layout object, it has no functionality associated with it.
Building forms manually is quite straight-forward but a bit more work.
Items
These should have the source set to "Static Text" rather than database column.
Buttons
You will need button like Create, Apply Changes, Delete that submit the page. These need unique request values so that you know which table is being processed, e.g. CREATE_EMP. You can make the buttons display conditionally, e.g. Create only when PK item is null.
Row Fetch Process
This will be a simple PL/SQL process like:
select ename, job, sal
into :p1_ename, :p1_job, :p1_sal
from emp
where empno = :p1_empno;
It will need to be conditional so that it only fires on entry to the form and not after every page load - otherwise if there are validation errors any edits will be lost. This can be controlled by a hidden item that is initially null but set to a non-null value on page load. Only fetch the row if the hidden item is null.
Submit Process(es)
You could have 3 separate processes for insert, update, delete associated with the buttons, or a single process that looks at the :request value to see what needs doing. Either way the processes will contain simple DML like:
insert into emp (empno, ename, job, sal)
values (:p1_empno, :p1_ename, :p1_job, :p1_sal);
Optimistic Locking
I omitted this above for simplicity, but one thing the built-in forms do for you is handle "optimistic locking" to prevent 2 users updating the same record simultaneously, with one's update overwriting the other's. There are various methods you can use to do this. A common one is to use OWA_OPT_LOCK.CHECKSUM to compare the record as it was when selected with as it is at the point of committing the update.
In fetch process:
select ename, job, sal, owa_opt_lock.checksum('SCOTT','EMP',ROWID)
into :p1_ename, :p1_job, :p1_sal, :p1_checksum
from emp
where empno = :p1_empno;
In submit process for update:
update emp
set job = :p1_job, sal = :p1_sal
where empno = :p1_empno
and owa_opt_lock.checksum('SCOTT','EMP',ROWID) = :p1_checksum;
if sql%rowcount = 0 then
-- handle fact that update failed e.g. raise_application_error
end if;
Another, easier solution for the fetching part is creating a view with all the feilds that you need.
The weak point is it that you later need to alter the "submit" code to insert to the tables that are the source for the view data