...前言 MySQL存储过程中,定义变量有两种方式: 1、使用set或select直接赋值,变量名以@开头 例如: set @var=1; 可以在一个会话的任何地方声明,作用域是整个会话,称为用户变量...2、以declare关键字声明的变量,只能在存储过程中使用,称为存储过程变量,例如: declare var1 int default 0; 主要用在存储过程...
CREATE[ORREPLACE]FUNCTIONname([[argmode][argname]argtype[{DEFAULT|=}default_expr][,...]])[RETURNSrettype|RETURNSTABLE(column_name column_type[,...])]{LANGUAGElang_name|TRANSFORM{FORTYPEtype_name}[,...]|WINDOW|IMMUTABLE|STABLE|VOLATILE|[NOT]LEAKPROOF|CALLEDONNULLINPUT|RETURNSNULLONNULLINPUT|...
SELECT INTO — 从一个查询的结果中定义一个新表 SET — 改变运行时参数 SET CONSTRAINTS — 设置当前事务的约束检查模式 SET ROLE — set the current user identifier of the current session SET SESSION AUTHORIZATION — 为当前会话设置会话用户标识符和当前用户标识符 SET TRANSACTION — 设置当前事务的特性 SH...
- The “DEFAULT” keyword initializes the given variable with a default or initial value. - The “:=” or “=” operator is used to initialize a variable. Let’s learn how to declare a variable in Postgres using the following examples. Example 1: How to Declare and Initialize the Varia...
set default_tablespace=表空间名称; 20.指定用户登录 psql MTPS -u 21.显示当前系统时间、 now() 22.配置plpgsql语言 CREATE LANGUAGE 'plpgsql' HANDLER plpgsql_call_handler 23.删除规则 DROP RULE name ON relation [ CASCADE | RESTRICT ] 输入
SET column = value, ... WHERE CURRENT OF cursor_variable; DELETE FROM table_name WHERE CURRENT OF cursor_variable; 1. 2. 3. 4. 5. 6. 示例: UPDATE film SET release_year = p_year WHERE CURRENT OF cur_films; 1. 2. 3. 四、关闭游标 ...
postgres=#DO$$postgres$#DECLAREpostgres$#nametext;postgres$#BEGINpostgres$#name:='PL/pgSQL';postgres$#RAISENOTICE'Hello %!',name;postgres$#END$$;NOTICE:HelloPL/pgSQL! 嵌套子块 PL/pgSQL 支持代码块的嵌套,也就是将一个代码块嵌入其他代码块的主体中。被嵌套的代码块被称为子块(subblock),包含子...
变量名 [constant] 类型 [not null] [:=value] 1. 注意:在声明部分,每一行只能有一个变量声明 【错误实例】 DECLARE v_firstname, v_lastname varchar2(20); 【正确示范】 DECLARE v_firstname varchar2(20); v_lastname varchar2(20); 变量的初始化 DECLARE v_counter number := 45; v_numberseat...
stmt :='delete from emp where deptno = :dept_array';/* A Dynamic SQL String with a bind variable */c :=DBMS_SQL.OPEN_CURSOR;/* Open a Cursor! */DBMS_SQL.PARSE(c, stmt, DBMS_SQL.NATIVE);/* Parse the Dynamic SQL , making it happen on the native database to which is connected...
Just as for DELETE, a CTID or whole-row variable is added so that the executor can identify the old row to be updated.Every entry in the target list contains an expression that can be a constant value, a variable pointing to a column of one of the relations in the range table, a ...