PRSQL9103055: Queries Using the MAX() Function May Run Slowly

ID Number: Q71297

1.10

OS/2

buglist1.10

Summary:

PROBLEM ID: PRSQL9103055

SYMPTOMS

When a query is run that selects the maximum value from a column

using the MAX() function, the query may run considerably slower

than similar queries that do not use the MAX() function. The same

query executed using the MIN() function may run much faster.

Although the query optimizer may take advantage of indexes on the

table, if they exist, the MAX() function will usually still execute

slower than the MIN() function.

CAUSE

This problem occurs on larger tables under certain circumstances

when using the MAX() function with a WHERE clause. The following is

an example of a query where this problem is evident:

SELECT max(custno) FROM cust

WHERE custno < 15000

STATUS

Microsoft has confirmed this to be a problem in SQL Server version

1.10. We are researching this problem and will post new information

here as it becomes available.