在plpgsql的循环中递增数字 [英] Incrementing a number in a loop in plpgsql

问题描述

我无法从示例中立即找到它.我想在一个函数的循环中增加一个变量.

I couldn't find this immediately from the examples. I want to increment a variable in a loop, in a function.

例如:

DECLARE
   iterator float4;
BEGIN
   iterator = 1;

    while iterator < 999
       .....
      iterator ++;
END;

这将如何完成?

我正在查看有关流量控制的这份文件:
http://www.postgresql.org/docs/8.4/static/plpgsql-control-structures.html

I was looking at this document about flow control:
http://www.postgresql.org/docs/8.4/static/plpgsql-control-structures.html

它们似乎与我无关，除非这些绝对是模拟增加变量的唯一方法.

And none of them seem to be relevant for me, unless these are absolutely the only ways to simulate incrementing a variable.

推荐答案

在plpgsql中递增变量:

To increment a variable in plpgsql:

iterator := iterator + 1;

没有++运算符.

关于plpgsql中的赋值运算符:

About the assignment operator in plpgsql:

• 被遗忘的赋值运算符"="和普通的":: ="

纠正循环语法在手册中的PL/pgSQL中.

您的代码片段将像这样工作:

Your code fragment would work like this:

DECLARE
   iterator float4 := 1;  -- we can init at declaration time
BEGIN
   WHILE iterator < 999
   LOOP
      iterator := iterator + 1;
      -- do stuff
   END LOOP;
END;

使用 FOR 循环:

   FOR i in 1 .. 999   -- i is integer automatically, not float4
   LOOP
      -- do stuff
   END LOOP;

手册:

变量name被自动定义为类型integer，并且仅在循环内部存在(变量名称的任何现有定义在循环内都会被忽略).

The variable name is automatically defined as type integer and exists only inside the loop (any existing definition of the variable name is ignored within the loop).

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