Oracle ( ) Joins converting to SQL Server-CodePudding

I have a query that uses the old style Oracle join syntax. I'm trying to convert this to T-SQL to reflect a data storage change.

My query is:

SELECT
    client_name1,
    personal_business_ind,
    birth_date,
    sex
FROM 
    client ce,
    exclusions_endorsements ee
WHERE 
    ce.client_reference = :clientid
    AND ee.fourth_insert( ) = ce.client_reference
    AND ee.identification_code( ) = 'OCCP1'
ORDER BY
    ee.run_date_last_trans DESC;

Could anyone please help?

I have tried the following query but it doesn't seem to produce the correct output on SQL Server:

SELECT
    client_name1,
    personal_business_ind,
    birth_date,
    sex
FROM 
    client ce,
RIGHT OUTER JOIN 
    [CLOAS].[EE_ExclusionsEndorsements] ee ON ee.fourth_insert = ce.client_reference AND ee.identification_code = 'OCCP1'
WHERE 
    ce.client_reference = @clientid
ORDER BY
    ee.run_date_last_trans DESC;

CodePudding user response：

That's "old" Oracle outer join operator. For example:

SQL> select d.deptno, max(e.ename) ename
  2  from dept d, emp e
  3  where e.deptno ( ) = d.deptno
  4  group by d.deptno
  5  order by d.deptno;

    DEPTNO ENAME
---------- ----------
        10 MILLER
        20 SMITH
        30 WARD
        40

You'd - instead - use

SQL> select d.deptno, max(e.ename) ename
  2  from dept d left join emp e on e.deptno = d.deptno
  3  group by d.deptno
  4  order by d.deptno;

    DEPTNO ENAME
---------- ----------
        10 MILLER
        20 SMITH
        30 WARD
        40

SQL>

Or, in your case,

SELECT
    client_name1,
    personal_business_ind,
    birth_date,
    sex
FROM exclusions_endorsements ee left join client ce on ee.fourth_insert = ce.client_reference
                                                   AND ee.identification_code = 'OCCP1'
WHERE 
    ce.client_reference = :clientid   
ORDER BY
    ee.run_date_last_trans DESC;

CodePudding user response：

You are close. But the outer joined table is exclusions_endorsements, not client, so you need a LEFT OUTER JOIN. And there is a comma too many after FROM client ce in your query.

One more point: Oracle sorts nulls first when ordering descendingly, SQL Server sorts them last. And SQL Server does not support standard SQL syntax NULLS FIRST. We need a case expression hence.

SELECT
    client_name1,
    personal_business_ind,
    birth_date,
    sex
FROM client ce
LEFT OUTER JOIN exclusions_endorsements ee
                  ON ee.fourth_insert = ce.client_reference
                 AND ee.identification_code = 'OCCP1'
WHERE 
    ce.client_reference = @clientid
ORDER BY
    CASE WHEN ee.run_date_last_trans IS NULL THEN 1 ELSE 2 END,
    ee.run_date_last_trans DESC;

I should add that the query would look better, did you qualify all columns. E.g. ce.client_name1. And sorting by a column you don't select can make the result look completely unordered. Well, maybe it's a non-nullable column, in that case it would just serve to get the outer-joined rows separated from the inner-joined rows in the result.