sql refactor

Label: Read Catalogue (1) Select the most efficient table name order (valid only in the rule-based optimizer) (2) connection order in the WHERE clause (3) Avoid using ' * ' in the SELECT clause (4) Reduce the number of accesses to the database (5) Reset the ArraySize parameter in Sql*plus, sql*forms and pro*c to increase the amount of data retrieved per database access, with a recommended

server | sqlserver | data | data type | conversion Why not let SQL Server automatically convert the data type in SQL command for you Report Date: 12/5/2003 Prepared by: Zheng Ye Article last modified on 2004-2-16 The information in this article applies to: ü Microsoft SQL Server 2000, 7.0 Problem statement: One day, execute SELECT * FROM XXX_ORIGINAL_20031205

Tags: migrating local SQL Server database to Windows Azure SQL database via SSMs toolMigrate local SQL Server database to Windows Azure SQL database via the SSMs toolMicrosoft's product updates are getting faster, almost every year there are product updates, today, we mainly introduce how to migrate the local

Tags: Microsoft CTI object Complex problem: Lis use parameter BinThis article belongs to theUnderstand the mysteries of performance-slow in applications, fast in SSMS"seriesNext: Understanding the Mysteries of performance-application slow, SSMs fast (5)--case: How to deal with parameter sniffing We put aside the argument sniffing topic and went back to the original point of concern in this series: Why is the statement slow in the application, but fast in ssms? So far, it's all about the stored p

. Because indexes require additional storage space and processing, those unnecessary indexes can slow query response time. It is necessary to periodically refactor the index.:ALTER INDEX 18) Replace distinct with exists:Avoid using DISTINCT in the SELECT clause when submitting a query that contains one-to-many table information, such as a departmental table and an employee table. It is generally possible to consider replacing with exist, EXISTS makes

modified. This means that each record's insert, DELETE, and update will pay more than 4, 5 disk I/O. Because indexes require additional storage space and processing, those unnecessary indexes can slow query response time. It is necessary to periodically refactor the index.:ALTER INDEX 18) Replace distinct with exists:Avoid using DISTINCT in the SELECT clause when submitting a query that contains one-to-many table information, such as a departmental t

1. View the version of the databaseSELECT @ @versionSeveral common types of SQL Server patched version numbers:8.00.194 Microsoft SQL Server 20008.00.384 Microsoft SQL Server SP18.00.532 Microsoft SQL Server SP28.00.760 Microsoft SQL Server SP38.00.818 Microsoft

1. view the database versionSelect @ version Common SQL server patch versions: 8.00.194 Microsoft SQL Server 20008.00.384 Microsoft SQL Server 2000 sp18.00.532 Microsoft SQL Server 2000 sp28.00.760 Microsoft SQL Server 2000 sp38.00.818 Microsoft

A big and comprehensive choice between SQL and functions: Who is a more effective SQL ?, More effective SQL Reprinted please indicate the source: jiq •'s technical Blog Note that the Oracle11g database is discussed here. It is not applicable to SQL Server, MYSQL, and other databases. 1. Problem Description There are t

Sharing the SQL area, private SQL area, and game Benchmark 1. Sharing the SQL area is another way to name the handle of the cursor object in Librarycace and the data of the Child heap. Ii. Concept of private SQL zone is stored in PGA in dedicated server mode. (Review the concept of PGA: PGA is allocated on the server s

1. sort by strokes of the Last Name: Select * From tablename order by customername collate chinese_prc_stroke_ci_as 2. database encryption:Select encrypt ('original password ')Select pwdencrypt ('original password ')Select pwdcompare ('original password', 'encrypted password') = 1 -- same; otherwise, different encrypt ('original password ')Select pwdencrypt ('original password ')Select pwdcompare ('original password', 'encrypted password') = 1 -- same; otherwise, different 3. Retrieve the fie

Many people do not know how SQL statements are executed in SQL Server, fearing that their written SQL statements will be misunderstood by SQL Server. Like what: SELECT * FROM table1 where name= ' Zhangsan ' and TID > 10000 and implementation: SELECT * FROM table1 where TID > 10000 and name= ' Zhangsan ' Some people

Tags: junction pool table Connection = = Employee Relationship Test Purpose allowsoptimization Problems of databasefirst, the question of the proposed In the early stage of application system development, due to less development database data, the query SQL statement, complex view of the writing of the performance of the SQL statement is not good or bad, but if the application system submitted to the actual

Label:Originally using SQL Server 2000 databases, the DTS tool makes it easy to import and export data between SQL Server and DBF files, and now, after installing SQL Server2005, discovers the SQL Server Import Export Wizard that it provides The data sources in the database are not rich in the original, and the DBF fil

Tags: Audit SQL ServerIntroductionAudit is a feature after SQL Server 2008 that tells you "who did what when?" Specifically, auditing an instance of the SQL Server database engine or a separate database involves tracking and documenting events that occur in the database engine. Its bottom-level is based on extended events (Extented event), so its performance and

What should I do if SQL Server executes dynamic SQL statements? The following describes the two correct ways for SQL Server to execute dynamic SQL. We hope that you can have a better understanding of SQL Server to execute dynamic SQL