variable相当于一个sql*plus环境的全局变量,declare里定义的是pl/sql中的局部变量。
create table T(col1 integer); insert into T values null; declare N integer not null := 0; null_variable exception; begin select col1 into N from T; if N is null then raise null_variable; end if; exception when null_variable then -- Handle error condition here. dbms_output.put_line...
variable相当于一个sql*plus环境的全局变量,declare里定义的是pl/sql中的局部变量。
三、declare--声明部分 plsql程序块的声明部分,内部变量,只在当前程序块有效。常量、变量、游标的声明都在declare部分。 Oracle定义变量的方式有3种: 声明并使用变量; 使用%TYPE声明变量类型; 使用%ROWTYPE声明变量类型 可以通过sys登录,使用"v$reserved_words"数据字典查看全部关键字 声明并使用变量 变量声明基本规则...
DECLARE @variable_name data_type [= value]; Declare statement @variable_name = variable’s name data_type = variable’s data type Value is an (optional) initial value to assign to the variable value. Let’s look at the query below to understand how the variable works in SQL Server. ...
CREATE PROCEDURE proc_vars() SPECIFIC proc_vars LANGUAGE SQL BEGIN DECLARE v_rcount INTEGER; DECLARE v_max DECIMAL (9,2); DECLARE v_adate, v_another DATE; DECLARE v_total INTEGER DEFAULT 0; -- (1) DECLARE v_rowsChanged BOOLEAN DEFAULT FALSE; -- (2) SET v_total = v_total + 1;...
在sqlplus 环境中,声明变量的关键字:define variable declare 一、define关键字(host变量) host变量的作用是一个替换作用,是主机环境与oracle进行交互的变量,定义host变量时必须同时指定变量名和变量的值,定义变量不可以指定数据类型,define定义的变量默认其数据类型都是char。该变量只在当前session起作用 ...
syntaxsql 复制 DECLARE { { @local_variable [AS] data_type } [ = value [ COLLATE <collation_name> ] ] } [ ,...n ] 参数@local_variable变量的名称。 变量名必须以 at 符 (@) 开头。 局部变量名称必须符合标识符规则。data_type 任何系统提供的公共语言运行时 (CLR) 用户定义表类型或别名数据...
DECLARE @@count int; SET @@count = 22; SELECT @@count END and this is the error message (not real helpful...): Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE @@count...
Oracle NoSQL Database allows implicit declaration of internal variables as well. Internal variables are bound to their values during the execution of the expressions that declare them. Variables (internal and external) can be referenced in other expressions by their name. In fact, variable referenc...