SQL Query选择'Next'记录（类似于First或Top N）

Question

I need to do a query to return the next (or prev) record if a certain record is not present. For instance consider the following table:

ID (primary key)    value
1                    John
3                    Bob
9                    Mike
10                   Tom.

I'd like to query a record that has id 7 or greater if 7 is not present.

My questions are,

1. Are these type of queries possible with SQL?
2. What are such queries called in the DB world?

Thanks!

Answer 1

Yes, it's possible, but implementation will depend on your RDBMS.

Here's what it looks like in MySQL, PostgreSQL and SQLite:

select ID, value
from YourTable
where id >= 7
order by id
limit 1

In MS SQL-Server, Sybase and MS-Access:

select top 1 ID, value
from YourTable
where id >= 7
order by id

In Oracle:

select * from (
    select ID, value
    from YourTable
    where id >= 7 
    order by id
)
where rownum = 1

In Firebird and Informix:

select first 1 ID, value
from YourTable
where id >= 7
order by id

In DB/2 (this syntax is in SQL-2008 standard):

select id, value
from YourTable
where id >= 7
order by id
fetch first 1 rows only

In those RDBMS that have "window" functions (in SQL-2003 standard):

select ID, Value
from (
  select 
    ROW_NUMBER() OVER (ORDER BY id) as rownumber,
    Id, Value
  from YourTable
  where id >= 7
) as tmp                  --- remove the "as" for Oracle
where rownumber = 1

And if you are not sure which RDBMS you have:

select ID, value
from YourTable
where id = 
      ( select min(id)
        from YourTable
        where id >= 7
      )

Answer 2

Try this for MS-SQL:

SELECT TOP 1 
id, value 
FROM your_table
WHERE id >= 7
ORDER BY id

or for MySql

SELECT id, value 
FROM your_table
WHERE id >= 7
ORDER BY id
LIMIT 0,1

Answer 3

I would simply do it like this:

select top 1 * from myTable where id >=7
order by id

implementation of the top 1 part is T-SQL (MSSQL/Sybase), other implementations vary but it is always possible (mysql/postgre LIMIT 1 , oracle rownum = 1 )

Answer 4

select top 1 * from Persons where Id >= @Id order by Id