Max and Min records from 2 tables

Question

I have 2 tables.

The 1st table have the columns fileID , createdate .

The 2nd table have the userid , fileID , createdate as common fields along with other columns.

I am trying to write a query to find latest fileid(max) and the 1st loaded fileid(min) based on the createdate for a specific userid by joining both these tables and using groupby on fileid, createdate in the query and filtering the user id in the where clause.

However the result is showing all the rows.

I need a suggestion as how to write a query inorder to get 2 records(max and min fileid records) only from both these tables and not all the records with these field changes.

I am using SQL Server to write the query.

Thanks for your help.

Answer 1

To select fieldid by earliest or lattest createdate and to have it in two separate rows you can try something like this:

SELECT fileid, "earliest" as type FROM table1 WHERE createdate = (SELECT MIN(createdate) from table1) LIMIT 1
UNION ALL
SELECT fileid, "lattest" as type FROM table1 WHERE createdate = (SELECT MAX(createdate) from table1) LIMIT 1

It is not clear, why you want to join it with the second table, but you can do it like this:

SELECT
 * 
FROM
  (
    SELECT fileid, "earliest" as type FROM table1 WHERE createdate = (SELECT 
    MIN(createdate) from table1) LIMIT 1
    UNION ALL
    SELECT fileid, "lattest" as type FROM table1 WHERE createdate = (SELECT 
    MAX(createdate) from table1) LIMIT 1
  ) as subquery1
LEFT JOIN
  table2 on table2.fileid = createdate.fileid