MySQL爆炸字符串并删除最后一部分

Question

我有像

这样的字符串

some1-some2-som3-123
some1-some2-143
some1-1235

如何移除上一部分-123？从该字符串与sql statment

Answer 1

您可以从头到尾使用简单的SUBSTRING -：

SELECT col, SUBSTRING(col, 0, LENGTH(col) - INSTR(REVERSE(col), '-')) AS result
FROM tab;

的 SqlFiddleDemo

输出：

╔═══════════════════════╦══════════════════╗
║         col           ║      result      ║
╠═══════════════════════╬══════════════════╣
║ some1-some2-som3-123  ║ some1-some2-som3 ║
║ some1-some2-143       ║ some1-some2      ║
║ some1-1235            ║ some1            ║
╚═══════════════════════╩══════════════════╝

Answer 2

DEMO

首先找到＆＃39; - ＆＃39;

的最后一个索引

SELECT LENGTH("first-middle-last") - LOCATE('-', REVERSE("first-middle-last"));

然后提取左侧部分 -

SELECT LEFT("first-middle-last", LENGTH("first-middle-last") - LOCATE('-', REVERSE("first-middle-last")));