Shulou(Shulou.com)05/31 Report--

This article will explain in detail how to implement progress optimization in SQL. The content of the article is of high quality, so the editor will share it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

Clustered index scan

SELECT * FROM C_SY_Ownedstorm

Clustered index scanning is faster than table scanning

Clustered index scan: occurs in a clustered table, which is also equivalent to a full table scan operation, but is more efficient in operations such as conditions for clustered columns.

Table scan

SELECT * FROM # temp

Table scan: when a table is stacked and no indexes are available, a table scan occurs, indicating that the entire table is scanned once.

Test SQL

CREATE TABLE T1 (C1 INT, c2 VARCHAR (8000)); GO DECLARE @ an INT; SELECT @ a = 1; WHILE (@ a)

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.