在SQL中获取字符串的长度 [英] Getting the length of a string in SQL

问题描述

我正在尝试获取SQL中字符串的长度(使用Firebird 2.x +版本).每当我选择一个字符串的长度时，它都会给我该字符串的实际分配的最大长度，而不是获取记录中记录了多少个字符的长度，如您在此处看到的:

I'm trying to get the length of a string in SQL (using Firebird version 2.x+). Whenever I select the length of a string it gives me the actual assigned maximum length of that string as opposed to getting the length of how many of the characters are taken in a record, as you can see here:

您可以想象，这对我没有帮助，因为我无法按长度排序，因为我试图按已分配了恒定长度的属性进行排序.

as you can imagine, this does not help me, as I can't order by the length, since I'm trying to order by an attribute that has a constant length assigned.

我将如何实现自己想要实现的目标?那就是:获取一个字符串中包含多少个字符的长度.

How would I achieve what I am trying to achieve? That is: getting the length of how many characters are taken in a string.

推荐答案

针对

注释

• 使用类型为 CHAR 的参数，此函数返回形式的字符串长度(即，字段或变量的声明长度).如果要获得逻辑"长度，而不计算尾随空格，请右键-

  Notes

  • With arguments of type CHAR, this function returns the formal string length (i.e. the declared length of a field or variable). If you want to obtain the "logical" length, not counting the trailing spaces, right-TRIM the argument before passing it to CHAR[ACTER]_LENGTH.

  这样做的原因是 char 值用空格填充到声明的长度，因此从本质上讲，它们是声明的长度.

  The reasons for this is that char values are padded with spaces to the declared length, so in essence they are of the declared length.

  换句话说，您需要使用:

  In other words you need to use:

  char_length(trim(trailing from imeprodajalca))
  

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