1. MY sql server

to use describe table which is used in mysql if we want to use it in server use
exec sp_help students - students is the table name
if we want to list all the table names like show tables in mysql
select name from sys.tables
for databases name listing do select name from sys.databases;
in sql server we dont have the limit keyword to limit show the rows so we use

select top 3 dept,count(name) from students
group by dept;

to rename a column name in sqlserver
exec sp_rename 'students.marks','student_marks','column';
use of procedure

create procedure sup 
as 
begin
select * from suppliers;
end
go

or with params

create procedure sup_name @city varchar(50)
as
begin
select * from suppliers where city=@city
end
go

--to run this
exec sup_name @city='surat';

questions

--select max marks from students
select top 1 * from students
order by marks desc;
select * from students where marks=(select max(marks) from students);

-- other method
select * from students
order by marks desc
offset 1 row fetch next 1 row only;

-- show names of students whoes names start with letter s
select * from students where name  like 's%';

-- select 2nd higest marks from students
select top 1 * from students where 
marks<(select max(marks) from students) 
order by marks desc;

-- select nth highest salary from students here 5th highest
select min(marks) as nhigh from (select top 5 name,marks from students order by marks desc) as temp ;

--or
select top 1 * from students where marks in(select top 5 marks from students order by marks desc) 
order by marks asc;

--or
select * from students
order by marks desc
offset 4 row  fetch next 1 row only;

-- select name from students where the 3rd letter is h for ignoring a letter use underscore
select * from students where name like '__h%';

"The WHERE clause is used to filter individual rows before any grouping happens, while the HAVING clause is used to filter groups after using GROUP BY.
For example, if I want to select only students who scored above 80, I use WHERE.
But if I want to find names of students who appear more than once, I group them by name and use HAVING COUNT(*) > 1."**

Bonus:

You can say:

"WHERE works on raw data, HAVING works on aggregated data."

That shows you understand when to use which.