Mysql retriving the nth record - mysql

Suppose I have a table named EMPLOYEE containing the following attributes
(EMPLOYEE_ID, LAST_NAME, FIRST_NAME, MIDDLE_NAME, JOB_ID, MANAGER_ID, Salary)
Can I
Display the Nth highest salary drawing employee details
Please help

ORDER BY and LIMIT where 10 is n + 1:
SELECT
*
FROM
employees
ORDER BY
Salary DESC
LIMIT
10, 1
(If you want the first record, use LIMIT 0, 1. For the tenth, use LIMIT 9, 1 etc.)

try this
put n > 1 to get corresponding results
n=3 must give you second highest salary
SELECT * --This is the outer query part
FROM Employee Emp1
WHERE (N-1) = ( /* Subquery starts here */
SELECT COUNT(DISTINCT(Emp2.Salary))
FROM Employee Emp2
WHERE Emp2.Salary > Emp1.Salary)

Test Table
CREATE TABLE Test
(ID INT IDENTITY(1,1),
Salary INT)
INSERT INTO Test
VALUES (100), (200), (300), (400), (500)
SELECT * FROM Test
Query
SELECT TOP 1 Salary
FROM
(SELECT TOP 3 Salary FROM Test ORDER BY Salary DESC)q
ORDER BY Salary ASC
In your Sub-query SELECT TOP Nth the rest remains the same and it will get you the desired results

Related

MySQL - joining a table to itself / sub queries

I'm asking for help on an assessment question I recently got wrong, I've tried a number of solutions and think I kind of know what I'm trying to do, but can't seem to figure out the syntax.
I have a table that looks like the below but with more records.
MyTable
ID Name DivisionID ManagerID Salary
123 John Smith 100 789 40000
456 Harold Johnson 101 null 60000
789 Vicky Brown 100 null 80000
and have to select the row of the person with the 3rd highest salary, which I had no problem with. However, I also need to return, instead of ManagerID, the Manager Name, which needs to be looked up from the same table.
I've tried the following solution which seems to be a bit inelegant and has to have the same query hard-coded within it, so not ideal for scaling or general use:
SELECT
table.ID,
Name,
DivisionID,
(SELECT
Name FROM table WHERE id=(
SELECT ManagerID FROM table ORDER BY Salary DESC LIMIT 2,1)
) AS ManagerName,
Salary
FROM table
ORDER BY Salary DESC LIMIT 2,1;
I think there may be some way of doing this with subqueries, e.g. first selecting a separate table within the query of just manager id and name, and then selecting from this - but I just can't seem to get the syntax right or get my head around it. I think it might also be possible with table aliases where I select two different results from the same table under different aliases and then join the two, but again just can't figure out how to do this. Below is what I've tried to do with aliases
SELECT
a.ID,
a.Name,
a.DivisionID,
b.Name AS ManagerName
a.Salary
FROM table a
INNER JOIN table b ON a.ManagerID=b.ID
ORDER BY Salary DESC LIMIT 2,1;
First of all, when asked to return the nth greatest/least value, you must ask back what to do in case of ties. They want the person with third highest salary, so with salaries 1000, 1000, 900, 900, 800, 800, 700, 600, 500, I'd suppose you want to return the persons that earn 800, because that is the third highest salary. If you just order the persons by salary, skip two and take the third, then you pick one of the persons with a salary of 900 arbitrarily, and 900 is not even the third highest, but the second highest salary.
In order to get the manager, simply join the table again. You should use an outer join for the case that an employee with the third highest salary is a manager themselves.
The straight-forward solution is to rank the rows with DENSE_RANK:
select *
from
(
select t.*, dense_rank() over (order by salary desc) as rnk
from mytable t
) employee
left join mytable manager on manager.id = employee.managerid
where employee.rnk = 3;
MySQL supports DENSE_RANK since version 8. In older versions you must look up the same table again. Select the distinct salaries and use your limit/offset clause on those saleries.
select *
from mytable employee
left join mytable manager on manager.id = employee.managerid
where employee.salary =
(
select distinct salary
from mytable
order by salary desc
limit 2, 1
);
Demo: https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=6b17e369fcd4f99ddc6c268de15f08a1
Maka a subquersy form you code for the thrd and join selj join the table
This works also in MySQL 5.7 and earlier
CREATE TABLE MyTable (
`ID` INTEGER,
`Name` VARCHAR(14),
`DivisionID` INTEGER,
`ManagerID` VARCHAR(4),
`Salary` INTEGER
);
INSERT INTO MyTable
(`ID`, `Name`, `DivisionID`, `ManagerID`, `Salary`)
VALUES
('123', 'John Smith', '100', '789', '40000'),
('456', 'Harold Johnson', '101', 'null', '60000'),
('789', 'Vicky Brown', '100', 'null', '80000');
SELECT m1.ID, m1.Name, m1. DivisionID,m2. Name, m1.Salary
FROM (SELECT `ID`, `Name`, `DivisionID`, `ManagerID`, `Salary` FROM MyTable ORDER BY Salary DESC LIMIT 2,1) m1 JOIN MyTable m2 on m1.ManagerID = m2.ID
ID | Name | DivisionID | Name | Salary
--: | :--------- | ---------: | :---------- | -----:
123 | John Smith | 100 | Vicky Brown | 40000
db<>fiddle here

In SQL, How to output "NULL" instead of " There are no results to be displayed" when there's no value to be exported

Using MySQL v8.0 right now.
The question is:
Write an SQL query to report the id and the salary of the second highest salary from the
Employee table. If there is no second highest salary, the query should
report null.
My dummy data is:
Create table If Not Exists Employee (id int, salary int);
insert into Employee (id, salary) values
(1, 100);
My ideal output is like this:
+------+--------+
| id | salary |
+------+--------+
| NULL | NULL |
+------+--------+
I used DENSE_RANK as a more straightforward way for me to solve this question:
WITH sub AS (SELECT id,
salary,
DENSE_RANK() OVER (ORDER BY salary DESC) AS num
FROM Employee )
SELECT id, salary
FROM sub
WHERE num = 2
But I have a problem exporting NULL when there's no second highest salary. I tried IFNULL, but it didn't work. I guess it's because the output is not actually null but just empty.
Thank you in advance.
WITH sub AS (
SELECT id,
salary,
DENSE_RANK() OVER (ORDER BY salary DESC) AS num
FROM Employee
)
SELECT id, salary
FROM sub
WHERE num = 2
UNION ALL
SELECT NULL, NULL
WHERE 0 = ( SELECT COUNT(*)
FROM sub
WHERE num = 2 );
https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=31f5afb0e7e5dce9c2c128ccc49a6f42
Just making your query a subquery and left joining from a single-row producing subquery seems to me the simplest approach:
select id, salary
from (select null) at_least_one_row
left join (
select id, salary
from (
select id, salary, dense_rank() over (order by salary desc) as num
from Employee
) ranked_employees
where num = 2
) second_highest_salary on true
(I usually prefer a subquery to a cte that's only used once; I find that obfuscatory.)

How to retreive 5 highest values from a table

I have table with 10 rows with employee id and salary.
I want get a table with 5 rows in order of the highest salary.
create table employee(
id int not null primary key,
employeeName VarChar(20),
salary int
);
Thank you.
You can use RANK(), or DENSE_RANK, or ROW_NUMBER().
For example:
select *
from (
select *,
rank() over(order by salary desc) as rk
from employee
) x
where rk <= 5
order by rk, employeename
See running example (that show 6 rows since two are tied in fifth place) at DBFidle.

Getting the 2nd highest salary after dpt ID input

I am trying to write this PL SQL query to get the second highest salary out of the table after input of the dpt ID.
I put this together but the query does not run after the input of the dpt ID.
CREATE TABLE OUTPUT_LOG
(my_column VARCHAR(250));
DECLARE
v_dpt_id
BEGIN
select dpt_id
into v_dpt_id
from employees
where dpt_id = inticap('&prompt_user');
select salary from
(select rownum n,a.* from
( select distinct salary from employees order by salary desc) a)
where n = 2;
insert into output_log (my_column)
VALUES (||first_name||' '||last_name||' '||salary||);
end;
SELECT my_column
FROM OUTPUT_LOG;
try this
you can simply change query as like
select * from employees where salary in
(
select salary from
(select rownum n,a.* from
( select distinct salary from employees where dpt_id = initcap('&prompt_user') order by salary desc) a
)
where n = 2
)
this query give all employees which have secode highest salary on their department.
i hope this may help.

Query to fetch second highest salary from table [duplicate]

What is the simplest SQL query to find the second largest integer value in a specific column?
There are maybe duplicate values in the column.
SELECT MAX( col )
FROM table
WHERE col < ( SELECT MAX( col )
FROM table )
SELECT MAX(col)
FROM table
WHERE col NOT IN ( SELECT MAX(col)
FROM table
);
In T-Sql there are two ways:
--filter out the max
select max( col )
from [table]
where col < (
select max( col )
from [table] )
--sort top two then bottom one
select top 1 col
from (
select top 2 col
from [table]
order by col) topTwo
order by col desc
In Microsoft SQL the first way is twice as fast as the second, even if the column in question is clustered.
This is because the sort operation is relatively slow compared to the table or index scan that the max aggregation uses.
Alternatively, in Microsoft SQL 2005 and above you can use the ROW_NUMBER() function:
select col
from (
select ROW_NUMBER() over (order by col asc) as 'rowNum', col
from [table] ) withRowNum
where rowNum = 2
I see both some SQL Server specific and some MySQL specific solutions here, so you might want to clarify which database you need. Though if I had to guess I'd say SQL Server since this is trivial in MySQL.
I also see some solutions that won't work because they fail to take into account the possibility for duplicates, so be careful which ones you accept. Finally, I see a few that will work but that will make two complete scans of the table. You want to make sure the 2nd scan is only looking at 2 values.
SQL Server (pre-2012):
SELECT MIN([column]) AS [column]
FROM (
SELECT TOP 2 [column]
FROM [Table]
GROUP BY [column]
ORDER BY [column] DESC
) a
MySQL:
SELECT `column`
FROM `table`
GROUP BY `column`
ORDER BY `column` DESC
LIMIT 1,1
Update:
SQL Server 2012 now supports a much cleaner (and standard) OFFSET/FETCH syntax:
SELECT [column]
FROM [Table]
GROUP BY [column]
ORDER BY [column] DESC
OFFSET 1 ROWS
FETCH NEXT 1 ROWS ONLY;
I suppose you can do something like:
SELECT *
FROM Table
ORDER BY NumericalColumn DESC
LIMIT 1 OFFSET 1
or
SELECT *
FROM Table ORDER BY NumericalColumn DESC
LIMIT (1, 1)
depending on your database server. Hint: SQL Server doesn't do LIMIT.
The easiest would be to get the second value from this result set in the application:
SELECT DISTINCT value
FROM Table
ORDER BY value DESC
LIMIT 2
But if you must select the second value using SQL, how about:
SELECT MIN(value)
FROM ( SELECT DISTINCT value
FROM Table
ORDER BY value DESC
LIMIT 2
) AS t
you can find the second largest value of column by using the following query
SELECT *
FROM TableName a
WHERE
2 = (SELECT count(DISTINCT(b.ColumnName))
FROM TableName b WHERE
a.ColumnName <= b.ColumnName);
you can find more details on the following link
http://www.abhishekbpatel.com/2012/12/how-to-get-nth-maximum-and-minimun.html
MSSQL
SELECT *
FROM [Users]
order by UserId desc OFFSET 1 ROW
FETCH NEXT 1 ROW ONLY;
MySQL
SELECT *
FROM Users
order by UserId desc LIMIT 1 OFFSET 1
No need of sub queries ... just skip one row and select second rows after order by descending
A very simple query to find the second largest value
SELECT `Column`
FROM `Table`
ORDER BY `Column` DESC
LIMIT 1,1;
SELECT MAX(Salary)
FROM Employee
WHERE Salary NOT IN ( SELECT MAX(Salary)
FROM Employee
)
This query will return the maximum salary, from the result - which not contains maximum salary from overall table.
Old question I know, but this gave me a better exec plan:
SELECT TOP 1 LEAD(MAX (column)) OVER (ORDER BY column desc)
FROM TABLE
GROUP BY column
This is very simple code, you can try this :-
ex :
Table name = test
salary
1000
1500
1450
7500
MSSQL Code to get 2nd largest value
select salary from test order by salary desc offset 1 rows fetch next 1 rows only;
here 'offset 1 rows' means 2nd row of table and 'fetch next 1 rows only' is for show only that 1 row. if you dont use 'fetch next 1 rows only' then it shows all the rows from the second row.
Simplest of all
select sal
from salary
order by sal desc
limit 1 offset 1
select * from (select ROW_NUMBER() over (Order by Col_x desc) as Row, Col_1
from table_1)as table_new tn inner join table_1 t1
on tn.col_1 = t1.col_1
where row = 2
Hope this help to get the value for any row.....
Use this query.
SELECT MAX( colname )
FROM Tablename
where colname < (
SELECT MAX( colname )
FROM Tablename)
select min(sal) from emp where sal in
(select TOP 2 (sal) from emp order by sal desc)
Note
sal is col name
emp is table name
select col_name
from (
select dense_rank() over (order by col_name desc) as 'rank', col_name
from table_name ) withrank
where rank = 2
SELECT
*
FROM
table
WHERE
column < (SELECT max(columnq) FROM table)
ORDER BY
column DESC LIMIT 1
It is the most esiest way:
SELECT
Column name
FROM
Table name
ORDER BY
Column name DESC
LIMIT 1,1
As you mentioned duplicate values . In such case you may use DISTINCT and GROUP BY to find out second highest value
Here is a table
salary
:
GROUP BY
SELECT amount FROM salary
GROUP by amount
ORDER BY amount DESC
LIMIT 1 , 1
DISTINCT
SELECT DISTINCT amount
FROM salary
ORDER BY amount DESC
LIMIT 1 , 1
First portion of LIMIT = starting index
Second portion of LIMIT = how many value
Tom, believe this will fail when there is more than one value returned in select max([COLUMN_NAME]) from [TABLE_NAME] section. i.e. where there are more than 2 values in the data set.
Slight modification to your query will work -
select max([COLUMN_NAME])
from [TABLE_NAME]
where [COLUMN_NAME] IN ( select max([COLUMN_NAME])
from [TABLE_NAME]
)
select max(COL_NAME)
from TABLE_NAME
where COL_NAME in ( select COL_NAME
from TABLE_NAME
where COL_NAME < ( select max(COL_NAME)
from TABLE_NAME
)
);
subquery returns all values other than the largest.
select the max value from the returned list.
This is an another way to find the second largest value of a column.Consider the table 'Student' and column 'Age'.Then the query is,
select top 1 Age
from Student
where Age in ( select distinct top 2 Age
from Student order by Age desc
) order by Age asc
select age
from student
group by id having age< ( select max(age)
from student
)
order by age
limit 1
SELECT MAX(sal)
FROM emp
WHERE sal NOT IN ( SELECT top 3 sal
FROM emp order by sal desc
)
this will return the third highest sal of emp table
select max(column_name)
from table_name
where column_name not in ( select max(column_name)
from table_name
);
not in is a condition that exclude the highest value of column_name.
Reference : programmer interview
Something like this? I haven't tested it, though:
select top 1 x
from (
select top 2 distinct x
from y
order by x desc
) z
order by x
See How to select the nth row in a SQL database table?.
Sybase SQL Anywhere supports:
SELECT TOP 1 START AT 2 value from table ORDER BY value
Using a correlated query:
Select * from x x1 where 1 = (select count(*) from x where x1.a < a)
select * from emp e where 3>=(select count(distinct salary)
from emp where s.salary<=salary)
This query selects the maximum three salaries. If two emp get the same salary this does not affect the query.