select count oracle

After listening to nearly 20 speeches in the last two days, I felt a lot of harvest, and the deepest feeling was that I still had a long way to go. There are several points to note:Listening to the old cat yesterday, it is a common problem that

1) count (1) compared to COUNT (*):1. If your data table does not have a primary key, then count (1) is faster than COUNT (*)2, if there is a primary key, then the primary key (Union primary key) as the count of the condition is also faster than

1. The difference between count (1), COUNT (*), and count (column name)Believe that you are always at work, or in the study of Count () in the end how to use faster. There has been a lot of doubt, some people say that count (*) faster, some people

Count1) with Count (*) Comparison: If your data table does not have a primary key, COUNT (1) than COUNT (*Fast If there is a primary key, then the primary key (the Federated primary key) as the count condition is also more than count (*) to be quick

The Count (*) or COUNT (1) or count ([column]) in the database is probably the most commonly used aggregate function. A lot of people actually have a clear distinction between the three. This article will describe the roles, relationships, and

A similar warning was found while looking at a client's database recovery log (File #N is offline, but was part of a online tablespace.), not previously noticed, this time by experimenting to reproduce the contentCreate a table spacesql> Create

Oracle basic concepts and comparison with informix I. ConceptsUser: informix directly uses the user management system of the operating system. Generally, root and informix are used as super operators to manage other users. Oracle has its own user

NonsenseIt's been about N years since the last time I contacted Oracle database, and the way Oracle works and some of the dots is special, it feels like a wonderful thing! Recently regained memory, has been tossing Oracle, because Oracle is

First, the questionToday there is a magical problem-there is data in the table, but the result of select COUNT (*) is 0.The initial manifestation of the problem is that the query report has no paging.At first, I thought it was a Java-side problem.

Oracle Count Millions paging query total number of records, total bar count optimizationOracle Count millions query total number of records, total bar count optimizationRecently do a project, do paging, found that paging query speed is very slow,