Within Oracle ApEx is it possible to join an actual table in your schema to an Oracle ApEx Collection, as I am having trouble doing so?
Basically have the following scenario:
select c001, -- employee id from collection
c002,
c003 -- employee dept no from collection
from apex_collections,
emp
where emp.id = c001
and emp.deptno = c003;
Is the above possible or am I missing something?
we can join apex collection with our schema tables..it will work..
select c001, -- employee id from collection
c002,
c003 -- employee dept no from collection
from apex_collections,
emp emp
where emp.empno = c001
and emp.deptno = c003;
/*
I have this table person (personid, ...., telephone_numbers)
in which the column "telephone numbers" is a nested table.
In the example below I'm trying to use this into collections and display the count of telephone numbers that the row has.
-- */
DECLARE
telno telephone_number_table; -- variable name and type.
cnt INTEGER;
BEGIN
SELECT p.telephone_numbers -- accept the nested table into the variable
INTO telno
FROM person p
WHERE p.personid = 1;
SELECT COUNT(*) -- I'm using COUNT(*) here, you can use your valid column listing.
INTO cnt
FROM person p
CROSS JOIN TABLE(telno) tel -- use a cross join with alias
WHERE p.personid = 1;
dbms_output.put_line(cnt);
END;
/
Related
I have 2 tables as following:
Tam trying to get the department name of each employee (DepName column in table Emp table) from Dep table:
I have written this query:
update Emp
set DepName= (
select DepName
from Dep
where array_to_string(EmpID, ',') like EmpID
);
It did not update the table Emp with the requested information, although I haven't got any error. Any help?
You can do:
update emp
set dept = d.depname
from dep
where emp.empid = any (dep.empid);
Having pointed that out, you should not do this. Instead, I would suggest that you have a proper link to the department table and use join to bring in the department name.
you have to convert id int to character varying array data type and then use contains operator with table dept and update as usual
UPDATE emp t1
SET dept = dname
from dept t2
where t2.eid #> concat(concat('{',(t1.id::text)),'}') ::varchar[]
https://dbfiddle.uk/?rdbms=postgres_9.6&fiddle=e5c24b26b3479b68adf0b17c2050f715
I'm working in an Oracle environment.
In a 1:M table relationship I want to write a query that will bring me each row from the "1" table and only 1 matching row from the "many" table.
To give a made up example... ( * = Primary Key/Foreign Key )
EMPLOYEE
*emp_id
name
department
PHONE_NUMBER
*emp_id
num
There are many phone numbers for one employee.
Let's say I wanted to return all employees and only one of their phone numbers. (Please forgive the far-fetched example. I'm trying to simulate a workplace scenario)
I tried to run:
SELECT emp.*, phone.num
FROM EMPLOYEE emp
JOIN PHONE_NUMBER phone
ON emp.emp_id = phone.emp_id
WHERE phone.ROWNUM <= 1;
It turns out (and it makes sense to me now) that ROWNUM only exists within the context of the results returned from the entire query. There is not a "ROWNUM" for each table's data set.
I also tried:
SELECT emp.*, phone.num
FROM EMPLOYEE emp
JOIN PHONE_NUMBER phone
ON emp.emp_id = phone.emp_id
WHERE phone.num = (SELECT MAX(num)
FROM PHONE_NUMBER);
That one just returned me one row total. I wanted the inner SELECT to run once for each row in EMPLOYEE.
I'm not sure how else to think about this. I basically want my result set to be the number of rows in the EMPLOYEE table and for each row the first matching row in the PHONE_NUMBER table.
Obviously there are all sorts of ways to do this with procedures and scripts and such but I feel like there is a single-query solution in there somewhere...
Any ideas?
I'd use a rank (or dense_rank or row_number depending on how you want to handle ties)
SELECT *
FROM (SELECT emp.*,
phone.num,
rank() over (partition by emp.emp_id
order by phone.num) rnk
FROM EMPLOYEE emp
JOIN PHONE_NUMBER phone
ON emp.emp_id = phone.emp_id)
WHERE rnk = 1
will rank the rows in phone for each emp_id by num and return the top row. If there could be two rows for the same emp_id with the same num, rank would assign both a rnk of 1 so you'd get duplicate rows. You could add additional conditions to the order by to break the tie. Or you could use row_number rather than rank to arbitrarily break the tie.
All above answers will work beautifully with the scenario you described.
But if you have some employees which are missing in phone tables, then you need to do a left outer join like below. (I faced similar scenario where I needed isolated parents also)
EMP
---------
emp_id Name
---------
1 AA
2 BB
3 CC
PHONE
----------
emp_id no
1 7555
1 7777
2 5555
select emp.emp_id,ph.no from emp left outer join
(
select emp_id,no,
ROW_NUMBER() OVER (PARTITION BY emp_id ORDER BY emp_id) as rnum
FROM phone) ph
on emp.emp_id = ph.emp_id
where ph.rnum = 1 or ph.rnum is null
Result
EMP_ID NO
1 7555
2 5555
3 (null)
If you want only one phone number, then use row_number():
SELECT e.*, p.num
FROM EMPLOYEE emp JOIN
(SELECT p.*,
ROW_NUMBER() OVER (PARTITION BY emp_id ORDER BY emp_id) as seqnum
FROM PHONE_NUMBER p
) p
ON e.emp_id = p.emp_id and seqnum = 1;
Alternatively, you can use aggregation, to get the minimum or maximum value.
This is my solution. Simple but maybe wont scale well for lot of columns.
Sql Fiddle Demo
select e.emp_id, e.name, e.dep, min(p.phone_num)
from
EMPLOYEE e inner join
PHONE_NUMBER p on e.emp_id = p.emp_id
group by e.emp_id, e.name, e.dep
order by e.emp_id;
And this fix the query you try
Sql Fiddle 2
SELECT emp.*, phone.num
FROM EMPLOYEE emp
JOIN PHONE_NUMBER phone
ON emp.emp_id = phone.emp_id
WHERE phone.num = (SELECT MAX(num)
FROM PHONE_NUMBER p
WHERE p.emp_id = emp.emp_id );
I have table
EMP(id int primary key, name varchar2(15), mgrID int).
Now this table contain all employees(including worker and manager) in company. mgrID column contain id of employee to whom they are reporting.
I want to list the name of worker who is not manager along with their name of manager.
What to do for such query.
I tried nested select query as follows:
select name, (select name from EMP where mgerID is NULL)
as Manager from EMP;
Will this query give proper result?
You could use a self-join:
SELECT e.name AS name, m.name AS manager_name
FROM emp e
JOIN emp m ON e.mgrid = m.id
Your query should fail because you sub-query is uncorrelated and will return multiple results if you have multiple top-level managers.
select name
, (select name from EMP b where b.ID = a.mgerID ) as Manager
from EMP a;
I think the self-join is the more canonical solution, but you should understand the correlated subquery as well as it has many application.
I have a table that contains empid, name, salary, hiredate, position and supervisor (which includes empid, not the name). How do I list the empid and name of all supervisors?
The output has to have to columns supervisor (and a list of their empid) and their names. This is the create statement used to create the Employee table:
/* Create table Employee */
IF OBJECT_ID('Employee', 'U') IS NOT NULL
DROP TABLE Employee
GO
CREATE TABLE Employee (
emp_id NCHAR(5),
name NVARCHAR(20),
position NVARCHAR(20),
hire_date DATETIME,
salary MONEY,
bcode NCHAR(3),
supervisor NCHAR(5)
)
I have tried a variety of statements using having statement and count but they don't seem to work.
select emp_id, name from employee where position='manager';
I tried this but it doesn't work. Anyone smart that knows how to do it?
You will have to join the table back on itself:
select a.name, a.position, a.hiredate, a.salary, a.supervisorid,
isnull(b.name, '') as SupervisorName
from EmployeeTable a
left join EmployeeTable b
on a.SupservisorID=b.ID
The left join will make sure that the employees who do not have supervisors are returned, and isnull(b.name, '<NONE>') can be used if you would like to have something other than NULL as a value in those cases.
SELECT e.empid ,ISNULL(b.name, 'No supervisor') SupervisorName
FROM employee e LEFT JOIN employee b
ON e.supervisorid = b.empid
Inner join will leave out the people who do not have a supervisor , Use left join to get all the employees
If you want supervisors only, you just need to select rows whose emp_id values are found in the supervisor column:
SELECT
SupervisorID = emp_id,
SupervisorName = name
FROM dbo.Employee
WHERE emp_id IN (SELECT supervisor FROM dbo.Employee)
;
I am trying to figure out some ways to accomplish this script. I import an excel sheet and then I need to populate 5 different tables based on this excel sheet. However for this example I just need help with the initial loop then I think I can work through the rest.
select distinct Department from IPACS_New_MasterList
where Department is not null
This provides me a list of 7 different departments.
Dep1, Dep2, Dep3, Dep4, Dep5, Dep6, Dep7
For each of these departments I need to perform some code.
Step #1:
Insert the department into table_one
I then need to keep the SCOPE_IDENTITY() for the rest of the code.
Step #2
perform the second loop (inserting all functions in that department into table2.
I'm not sure how to really do a foreach row in this select statement loop, or if I need to do something completely different. I've looked at several answers but can't seem to find exactly what I'm looking for.
Sample Data:
Source Table
Dep1, func1, process1, procedure1
dep1, func1, process1, procedure2
dep1, func1, process2, procedure3
dep1, func1, process2, procedure4
dep1, func1, process2, procedure5
dep1, func2, process3, procedure6
dep2, func3, process4, procedure7
My Tables:
My first table is a list of every department from the above query. With a key on the departmentID. Each department can have many functions.
My second table is a list of all functions with a key on functionID and a foreign key on departmentID. Each function must have 1 department and can have many processes
My third table is a list of all processes with a key on processID and a foreign key on functionID. Each process must have 1 function and can have many procedures.
There are two approaches you can use without a loop.
1) If you have candidate keys in your source (department name) just join your source table back to the table you inserted
e.g.
INSERT INTO Department
(Name)
SELECT DISTINCT Dep1
FROM SOURCE;
INSERT INTO Functions
(
Name,
DepartmentID)
SELECT DISTINCT
s.Func1,
d.DepartmentID
FROM
source s
INNER JOIN Department d
on s.dep1 = d.name;
INSERT INTO
processes
(
name,
FunctionID,
[Procedure]
)
SELECT
s.process1,
f.FunctionID,
s.procedure1
FROM
source s
INNER JOIN Department d
on s.dep1 = d.name
INNER JOIN Functions f
on d.DepartmentID = f.departmentID
and s.func1 = f.name;
SQL Fiddle
2) If you don't have candidate keys in your source then you can use the output clause
For example here if a department weren't guaranteed to be unique this would correctly find only the newly add
DECLARE #Department TABLE
(
DepartmentID INT
)
DECLARE #Functions TABLE
(
FunctionID INT
)
INSERT INTO Department
(Name)
OUTPUT INSERTED.DepartmentID INTO #Department
SELECT DISTINCT Dep1
FROM SOURCE
INSERT INTO Functions
(
Name,
DepartmentID)
OUTPUT INSERTED.FunctionID INTO #FunctionID
SELECT DISTINCT
s.Func1,
d.DepartmentID
FROM
source s
INNER JOIN Department d
on s.dep1 = d.name
INNER JOIN #Department d2
ON d.departmentID = d2.departmentID;
INSERT INTO
processes
(
name,
FunctionID,
[Procedure]
)
SELECT
s.process1,
f.FunctionID,
s.procedure1
FROM
source s
INNER JOIN Department d
on s.dep1 = d.name
INNER JOIN Functions f
on d.DepartmentID = f.departmentID
and s.func1 = f.name
INNER JOIN #Functions f2
ON f.Functions = f2.Functions
SELECT * FROM Department;
SELECT * FROm Functions;
SELECT * FROM processes;
SQL Fiddle
If I am understanding what you are trying to do... yes you can use a loop. Its not really talked about and I bet I am going to get some feedback from other SQL developers that its not a best practice. But if you really need to do a loop
DECLARE #rowcount as int
DECLARE #numberOfRows as int
SET #rowcount = 0
SET #numberOfRows = SELECT COUNT(*) from tablename --put in anything to get the number of times to loop.
WHILE #numberOfRows <= #rowcount
BEGIN
--Put whatever process you need to repeat here
SET #rowcount = #rowcount + 1
END
Assuming you have tables set up with an IDENTITY field set for the Primary Key, you can populate each successive table's foreign key by joining to the previous table and the source table, something like:
INSERT INTO Table1
SELECT DISTINCT Department
FROM SourceTable
GO
INSERT INTO Table2
SELECT DISTINCT b.Deptartment_ID, a.Function
FROM SourceTable a
JOIN Table1 b
ON a.Department = b.Department
GO
INSERT INTO Table3
SELECT DISTINCT b.Function_ID, a.Process
FROM SourceTable a
JOIN Table2 b
ON a.Function = b.Function
GO
INSERT INTO Table4
SELECT DISTINCT b.Process_ID, a.Procedure
FROM SourceTable a
JOIN Table3 b
ON a.Process = b.Process
GO