sql set variable from select

Transferred from: http://www.cnblogs.com/micheng11/archive/2008/07/08/1237905.htmlThere are two ways to assign values to variables that are already defined in SQL Server, SET and SELECT, respectively.The differences between these two approaches are

SQL Server recommends assigning a variable using SET instead of SELECT.The SET method is recommended when an expression returns a value and assigns a variable.The following table lists the differences between SET and SELECT. Please pay special

*sql optimization based on ORACLE11GR2 reading notes * Third, cursor in OracleThe cursor in Oracle is a vector of SQL parsing and execution in an Oracle database and is a data structure for C (Oracle is written in C).There are two types of cursor in

Oracle SQL * plus is a client tool that interacts with oracle. In SQL * plus, you can run the SQL * plus command and the SQL * plus statement. The DML, DDL, and DCL statements we usually call are SQL * plus statements. After they are executed, they

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

Oracle SQL * plus is a client tool that interacts with oracle. In SQL * plus, you can run the SQL * plus command and the SQL * plus statement. The DML, DDL, and DCL statements we usually call are SQL * plus statements. After they are executed,

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

There are two ways to assign values to variables that are already defined in SQL Server, SET and SELECT, respectively.The differences between these two approaches are explained in more detail in SQL Server Books Online, but many times weDid not

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,

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