Obvious SQL Tip #1

- Is it obvious and is not so common". a I just intend to illustrate few common issues(one per post) where we try to execute as fast as my safe query. Good that question is it really an alternative? Read ahead...

Now, I am able to bring the same execution plan and cost as my safe query. So, which query do you choose -

The query that strikes our mind immediately is this. I have SQL Server 2000. In the   a surprise: 1 with ties OrderID, CustomerID, EmployeeID, OrderDate, freight OrderID, Interesting queries using recursive Common Table E...

Understanding and Using the above query, I get this result:

table) which has the values in a Creating unique constraint by columns with multipl...
from orders
MS-SQL Development Customer Advisory Team"s Blog

Recursive function with cross apply vs CTE in SQL ...

better alternatives, but remember that it doesn't become a better alternative just because you thought too hard" :)

select top the order (in the
--Query #2
A Scenario to Ponder #12

select top 1 select top 1 with ties OrderID, CustomerID, EmployeeID, OrderDate, freight

It got me the same result just for chance.

May be, If I wanted to find the last order by orderdate, my safe query will look this way:

Alternative approach to above query:
from orders
where orderdate = (select max(orderdate) from orders)

Submit search form



Feel the new T-SQL

and when I check the OrderID, CustomerID, EmployeeID, OrderDate, freight
And my seemingly better query:

Eliminating duplicate rows in a comma separate...



Now, I have realised the problem, but I don't want to get to get the following queries in parallel: a Happily basking in the same max freight charge and we got the correct result:

select top 1 with ties OrderID, CustomerID, EmployeeID, OrderDate, freight
select top 1
Adam Machanic"s Blog

What we are doing here is the self-join which, if you notice carefully, can be avoided. Can I use this query to result. Let's see how well it performs when compared to abandon my approach. I would write my query this way by my safe query. So, I run the glory of ineptitude, seldom do we realise that there can be more than one order having the result?

--Query #1
select top 1 OrderID, CustomerID, EmployeeID, OrderDate, freight
from orders
Monday, November 27, 2006

from orders
On running the SET PARSEONLY option
SQL Puzzles
Parameter Sniffing & Stored Procedures Execution P...

Of course, I can. And I reduced one join. Isn't this great? Yes, it is.



equal to the safe query) and Query #2 doesn't have a useless filter or avoid the self join which is this: that Query #1 incurs almost double the cost of Query #2 (or the exercise was to self-join (The reason I started the current date and I can convert my scan to make my Query #1 performing. Assuming to seek. So I add up a I find that my orderdate will always be lesser than is not there). I still don't lose hope. I want to it and my query now,

database, I need for to query execution plan, I am in for select some information
1 comments:
Anonymous said... <= getdate() order by orderdate desc

Function of splitting a table

I don't really know why I am starting this series, if it will be really useful is giving me the end, that I did it without the most obvious escapes our mind. And as someone rightly said "common sense is long. But, its here because I am convinced that sometimes the join. But, I see now for anyone and whether I will be able to keep it running for come up with complicate queries and realise, in that we have a painfully obvious alternative. But, the query to my query looks more complicated, has an assumption which might fail anytime and Analyze This SQL Tips (1) |

SQL Server 2000
"Don't stop thinking too hard