1、条件 对于条件控制结构,支持IF与CASE两种,IF语句有如下三种写法: if ... then ... end if if ... then ... else ... end if if ... then ... elsif ... then ... else ... end if 1. 2. 3. 以及CASE有两种写法: case ... when ... then ... else ... end case case when...
IF … THEN … END IF IF … THEN … ELSE … END IF IF … THEN … ELSIF … THEN … ELSE … END IF 具体语法官方文档链接中可查看,现在举个小例子看一个 代码语言:javascript 复制 CREATEORREPLACEFUNCTION"public"."func1"("a"int4)RETURNS"pg_catalog"."text"AS$BODY$ declare rel varchar;BEGI...
a := 0; if c.hd < to_date('1995-1-1', 'yyyy-mm-dd') then a := 0.05; elsif c.hd < to_date('1998-1-1', 'yyyy-mm-dd') then a := 0.03; else a := 0.01; end if; temp := temp + c.sal * a; update employees set salary = salary * (1 + a) where employee_id ...
在一个函数中执行插入、删除和更新的If Else语句是一种常见的数据库操作方式,可以根据特定条件执行不同的操作。下面是一个示例: 代码语言:sql 复制 CREATEORREPLACEFUNCTIONexample_function(conditionBOOLEAN)RETURNSVOIDAS$$BEGINIFconditionTHEN-- 执行插入操作INSERTINTOtable_name(column1,column2)VAL...
PostgreSQL offers some control statements such as“if”,“if then else”, and“if then elsif”that are used to control the flow of a program. These statements are also known as conditional statements or control statements. All these statements execute a command or set of commands based on a...
IF语句 PL/pgSQL 提供了三种形式的 IF 语句 • IF … THEN … END IF • IF … THEN … ELSE … END IF • IF … THEN … ELSIF … THEN … ELSE … END IF 示例代码: DO $$ DECLARE i INTEGER := 3; j INTEGER := 3; BEGIN ...
29ifthenelse30ifconditionthen31statement1;32else33statement2;34endif;3536案例:37do $$38declare39ainteger:=10;40binteger:=20;41begin42ifa>bthen43raise notice'a is greater then b';44else45raise notice'a is not greater then b';46endif;4748end; $$495051523、语法:53ifconditionthen54statement1...
CREATE OR REPLACE FUNCTION cs_fmt_browser_version(v_name varchar, v_version varchar) RETURNS varchar AS $$ BEGIN IF v_version IS NULL THEN RETURN v_name; END IF; RETURN v_name || '/' || v_version; END; $$ LANGUAGE plpgsql; plv8(可参考: pgxn.org/dist/plv8/doc/): //安装插件...
(比如锁超时异常),则重试exceptionwhenothersthen-- 重试次数显示raisenotice'retry: %', steps;-- 睡眠performpg_sleep(sleepts);-- 如果重试次数达到,还没有切换成功,则返回切换不成功ifsteps >= retrythenreturnfalse;else-- 递归调用,重试,传入参数重试次数+1.returnexchange_tab(nsp, from_tab, to_tab, ...
PERFORM select 1 from tbl where xxx limit 1; if found then xxx else xxx end if; 执行返回单行的表达式或QUERY,并将结果存入变量。 SELECT select_expressions INTO [STRICT] target FROM ...; INSERT ... RETURNING expressions INTO [STRICT] target; UPDATE ... RETURNING expressions INTO [STRICT] ...