truncate statement in sql

--1 Use master Backup Database Logtest To Disk= ' D:\\Program Files\\Microsoft SQL Server\\mssql10. Mssqlserver\\mssql\\backup\\logtest.bak ' With format --2 Use Logtest CREATE TABLE table_1 (Id int, test varchar (max)) Insert Table_1 (Id,test) VALUES (1, ' 3333 '); Insert Table_1 (Id,test) VALUES (2, ' 4333 '); Insert Table_1 (Id,test) VALUES (3, ' 5333 '); Use master --2.1 WAITFOR DELAY ' 00:00:05 ' Go Use Logtest

SQL statement optimization improves database performance and SQL statement database performance In systems with unsatisfactory performance, apart from the fact that the application load exceeds the server's actual processing capacity, it is more because the system has a large number of

Select from t anywhere, replace "" with a specific field list, and do not return any fields that are not available20, as far as possible to use Varchar/nvarchar instead of Char/nchar, because the first variable long field storage space is small, you can save storage space, and secondly for the query, in a relatively small field search efficiency is obviously higher.21, try to use numeric fields, if only the value of the field is not designed as a character type, which will reduce the performanc

Label: conn =mysqljdbcutils.getconnection (); Statement PS=conn.createstatement (); Ps.addbatch ("Truncate Qb_showcount_asite_copy"); Ps.executebatch (); String Srcsql= "SELECT Convert" (Unhex (Hex (CONVERT (Community using latin1)) using UTF8) as Community, PID from Qb_menbercmmsets_list whe Re site=7 "; stmt=conn.preparestatement (Srcsql); RS=Stmt.executequery (); Above is the empty command that executes

Experience in SQL statement optimization and SQL statement Optimization (1) select the most efficient table name sequence (only valid in the rule-based seo/'target = '_ blank'> Optimizer ): the ORACLE parser processes the table names in the FROM clause in the order FROM right to left. The table written in the FROM clau

SQL statement optimization principle and SQL statement optimization. SQL statement optimization principle: optimize SQL statements to process more than one million data to improve query

SQL UNION operatorThe UNION operator is used to combine the result set of two or more SELECT statements.Note that the SELECT statement inside the UNION must have the same number of columns. The column must also have a similar data type. Also, the order of the columns in each SELECT statement must be the same.SQL UNION SyntaxSELECT column_name (s) from Table_name1

fact there is only one member table and one distributed partitioned view per server. The location of the data is transparent to the application. One, rebuilding the indexDBCCREINDEX,DBCCIndexdefrag, shrinking data and logsDBCCSHRINKDB,DBCCshrinkfile. Set up automatic shrink logging. For large databases do not set up automatic database growth, it can degrade server performance. In T-There is a lot of emphasis on the way SQL is written, and here's a li

Required SQL statement (4) data deletion and update, SQL statement 1. Delete 1) delete recordsDelete from table name where id = 'xx' 2) Delete all data and return to the initialization Id field.Truncate table name 3) differences between delete and truncateA. truncate ena

SQL statement Optimization principles, SQL statement optimization Ways to improve query speed with data above millions: 1. Try to avoid using the! = or 2. To optimize the query, avoid full-table scanning as far as possible, and first consider establishing an index on the columns involved in the Where and order by.3.

SQL statement optimization introduction and SQL statement Optimization 1. To optimize the query, try to avoid full table scanning. First, consider creating an index on the columns involved in where and order. 2. Try to avoid null value determination on the field in the where clause. When creating a table, NULL is the d

Summary of common SQL statement optimization techniques [classic] and SQL statement techniques classic This example summarizes common SQL statement optimization techniques. We will share this with you for your reference. The detai

SQL statement join Table query and SQL statement join query Answers to questions about SQL statement join Table query 1. Create two databases: Database A (table a) and database B (table B ). 2. allocate the same account permissi

Label:The person who writes the program often needs to analyze whether the SQL statement that has been written has been optimized, and how fast the server responds, this time it needs to use the statistics state value of SQL to view it. by setting Statistics we can view the system situation when executing SQL. The opti

for a specific statement than index scan, we can instruct the optimizer to use full table scan. In Oracle, hints (prompt) is added to the statement to optimize the intervention optimizer. Hints is a mechanism provided by oracle to tell the optimizer to generate an execution plan as we tell it. We can use hints to implement: 1. Type of optimizer used 2. The optimization goal of the cost-based optimizer is a

. connection types between tables 5. Connection sequence between tables 6. Parallel statement degree In addition to the "RULE" prompt, once other prompts are used, the statement will be automatically changed to the CBO optimizer. If your data dictionary does not contain statistics, the default statistical data is used. Therefore, it is recommended that you perform regular analysis on tables and indexes if y

ThinkPHP -- SQL query statement, ThinkPHP -- SQL statement I. Query Method ThinkPHP provides three basic query methods: String condition query, Index Array condition query, and object bar query. Component query. In most cases, we recommend that you use index arrays and objects as the query conditions, because they are

The SQL statement with parameters is executed on the database. Exec sp_executesql Eg: Exec sp_executesql N'Insert into lcs_sys_model ([model_guid], [model_name], [model_desp], [model_issys]) values (@ model_guid, @ model_name, @ model_desp, @ model_issys )', N' @ model_guid uniqueidentifier, @ model_name nvarchar (50), @ model_desp nvarchar (500), @ model_issys bit', @ Model_guid = 'f3cd1369-58c

Detailed description of SQL statement execution sequence and SQL statement execution sequence Most of us do not need to deal with databases when we develop software. Especially for erp development, we have to deal with databases more frequently, because SQL is different from

Use an SQL statement that has been running for a long time in the mail, and send an SQL statement in the mail ALTER proc [dbo].[usp_EmailLongRunningSQL]asbegindeclare@LongRunningQueries AS TABLE( lrqId int IDENTITY(1,1) PRIMARY KEY, spid int NULL, batch_duration bigintNULL, program_namenvarchar(500) NULL, hostname