声明变量
声明变量的语法为:name [ CONSTANT ] type [ COLLATE collation_name ] [ NOT NULL ] [ { DEFAULT | := | = } expression ]; 声明变量的语法为:name [ CONSTANT ] type [ C
声明变量
声明变量的语法为:name [ CONSTANT ] type [ COLLATE collation_name ] [ NOT NULL ] [ { DEFAULT | := | = } expression ]; 声明变量的语法为:name [ CONSTANT ] type [ C