详解SqlServer 表达式(expression)

时间：2021-12-21 10:09:57|栏目：MsSql|点击：次

2 具体内容

2.1 使用范围

SQL Server（2008开始）；Azure SQL数据库；Azure SQL数据仓库；并行数据仓库

2.2 语法

是SQL Server数据库引擎评估以获取单个数据值的符号和运算符的组合。简单表达式可以是单个常量，变量，列或标量函数。运算符可用于将两个或多个简单表达式连接到一个复杂的表达式中。

-- Syntax for SQL Server and Azure SQL Database 
{ constant | scalar_function | [ table_name. ] column | variable 
 | ( expression ) | ( scalar_subquery ) 
 | { unary_operator } expression 
 | expression { binary_operator } expression 
 | ranking_windowed_function | aggregate_windowed_function 
}
-- Syntax for Azure SQL Data Warehouse and Parallel Data Warehouse 
-- Expression in a SELECT statement 
<expression> ::= 
{ 
 constant 
 | scalar_function 
 | column 
 | variable 
 | ( expression ) 
 | { unary_operator } expression 
 | expression { binary_operator } expression 
} 
[ COLLATE Windows_collation_name ] 
-- Scalar Expression in a DECLARE, SET, IF…ELSE, or WHILE statement 
<scalar_expression> ::= 
{ 
 constant 
 | scalar_function 
 | variable 
 | ( expression ) 
 | (scalar_subquery ) 
 | { unary_operator } expression 
 | expression { binary_operator } expression 
} 
[ COLLATE { Windows_collation_name ]

2.3 参数