sql if variable

Grammar:identifier [CONSTANT] datatype [not NULL] [: = | DEFAULT Expr]Identifier: Used to specify the name of a variable or constant.CONSTANT: Used to specify constants. When you define a constant, you must specify its initial value, and its value

*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

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

-How to determine if a binding variable exists in the system:Start by creating a table that holds the data you've collated:CREATE table T1 as select Sql_text from V$sqlarea;----V$sqlarea This view keeps track of shared cursor in all shared

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

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

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

OverviewVariables are an essential part of a language, and of course, the same is true for T-SQL. Variables are often seldom used in simple queries, but they are an essential part of complex queries or stored procedures.Types of variablesIn T-SQL,

Variable introduction when writing a PL/SQL program, you can define variables and constants, including: 1 in a PL/SQL program, scalar type (scalar) 2), composite type (composite)--for manipulating a single record 3), reference type (reference)--

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,