sql case statement
Using a SELECT statement with a simple CASE expression 在SELECT 语句中,CASE 简单表达式只能用于等同性检查,而不进行其他比较。 下面的示例使用 CASE 表达式更改产品系列类别的显示,以使这些类别更易于理解。 USE AdventureWorks2012; GO SELECT ProductNumber, Category = CASE ProductLine WHEN 'R' THEN 'Road' ...
Transact-SQL Syntax Conventions (Transact-SQL) Tutorial: Writing Transact-SQL Statements + (Add) (Transact-SQL) + (Unary Plus) (Transact-SQL) + (String Concatenation) (Transact-SQL) += (Add EQUALS) (Transact-SQL) += (String Concatenation) (Transact-SQL) - (Negative) (Transact-SQL) - (...
SQL Server allows for only 10 levels of nesting inCASEexpressions. TheCASEexpression can't be used to control the flow of execution of Transact-SQL statements, statement blocks, user-defined functions, and stored procedures. For a list of control-of-flow methods, seeControl-of-Flow Language (...
SQL Server allows for only 10 levels of nesting inCASEexpressions. TheCASEexpression can't be used to control the flow of execution of Transact-SQL statements, statement blocks, user-defined functions, and stored procedures. For a list of control-of-flow methods, seeControl-of-Flow Language (...
是一种在Transact-SQL中用于条件判断和分支控制的语句。它允许根据不同的条件执行不同的代码块。Case语句有两种形式:简单Case表达式和搜索Case表达式。 1. 简单Case表达式:简...
从他的阶梯到t - sql DML,Gregory Larsen涵盖了t - sql语言的更高级的方面,如子查询。 There are times where you need to write a single TSQL statement that is able to return different TSQL expressions based on the evaluation of another expression. When you need this kind of functionality you ca...
The simple CASE statement has the following structure: CASE selector WHEN selector_value_1 THEN statements_1 WHEN selector_value_1 THEN statement_2 ... ELSE else_statements END CASE;Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) Let’s examine the syntax of the simple CASE st...
SQL CASE The SQLCASEstatement evaluates a list of conditions and adds a column with values based on the condition. For example, -- add a new column 'order_volume' in the Orders table-- and flag any order greater than 10000 as 'Large Order'-- and smaller than 10000 as 'Small Order'...
CASE 语句在指定的搜索条件为 true 时执行一条或多条语句。 CASE 是独立的语句,它与必须作为表达式组成部分出现的 CASE 表达式不同。 CASE 语句有两种形式:简单 CASE 语句和搜索型 CASE 语句。 简单CASE 语句 (PL/SQL) 简单CASE 语句尝试将表达式 (称为选择器) 与一个或多个 WHEN 子句中指定的另一个表达式...