MS SQL Server Query optimization methodThere are many reasons for the slow speed of queries, which are common1, no indexes, or no indexes (this is the most common problem with query slowness, is the flaw in programming)2, I/o throughput is small,
First, let's look at the sample SQL statement to be parsed:
Copy codeThe Code is as follows: select * from dual
SELECT * frOm dual
Select C1, c2 From tb
Select c1, c2 from tb
Select count (*) from t1
Select c1, c2, c3 from t1 where condi1 = 1
Select
Paip. program function time performance optimization and SQL statement Optimization
Author attilax,1466519819@qq.com
Tracking Tool xdebug ..1
Profiler log analysis tool wincachegrind.2
Obtain the complete SQL statement from the code for testing..
For more information about bugs fixed in SQL Server 2000 Service Pack 4, click the following article number to view the article in the Microsoft Knowledge Base:314128 FIX: When an RPC call is performed, Access with conflicting values includes an
35. use SQL query analyzer and SQL profilerUse SQL query AnalyzerUse SQL profilerOptimize T-SQL statementSummaryIn this chapter, we will continue with the description of the pre-stored procedures in Chapter 21st. This chapter describes how to use
sql| News | web | statement
1,select Statement
In the SQL world, the most fundamental operation is the SELECT statement. Many people will be familiar with the following when using SQL directly under Database Tools:
SELECT whatFrom whichtableWHERE
Chapter 4 SQL statement ProcessingBefore adjustment, we need to know some background knowledge. Only by knowing this background knowledge can we better adjust SQL statements.This section describes the basic process of SQL statement processing,
SQL statement + select top usage of "Fetch 10th to 20th records from a data table", 10th SQL statements
1. First, select top usage:
For more information, see the differences between select top n * from and select * from.
Select * from table --
13. T-SQL and SQL query AnalyzerWhat is SQL?What is T-SQL?Introduce new features of T-SQLHow to Use T-SQLSummaryIn this chapter, we will introduce some basic concepts about the Structured Query Language and transact-SQL and their differences. This
The following statements are part of a MSSQL statement and cannot be used in access.
SQL Category:
ddl-Data Definition language (create,alter,drop,declare)
dml-Data Manipulation Language (Select,delete,update,insert)
dcl-Data Control Language
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