2 具體內(nèi)容
2.1 使用范圍
SQL Server(2008開始) ;Azure SQL數(shù)據(jù)庫;Azure SQL數(shù)據(jù)倉庫;并行數(shù)據(jù)倉庫
2.2 語法
是SQL Server數(shù)據(jù)庫引擎評(píng)估以獲取單個(gè)數(shù)據(jù)值的符號(hào)和運(yùn)算符的組合。簡(jiǎn)單表達(dá)式可以是單個(gè)常量,變量,列或標(biāo)量函數(shù)。運(yùn)算符可用于將兩個(gè)或多個(gè)簡(jiǎn)單表達(dá)式連接到一個(gè)復(fù)雜的表達(dá)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::= { 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 ::= { constant | scalar_function | variable | ( expression ) | (scalar_subquery ) | { unary_operator } expression | expression { binary_operator } expression } [ COLLATE { Windows_collation_name ]