详解SqlServer 表达式(expression)

2020-07-25 11:52:35

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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