MySQL的爆炸字符串，删除最后一部分

Question

我有串状

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

如何删除最后一部分-123？从该字符串与SQL statment

Answer 1

您可以使用简单的SUBSTRING从开始到最后-：

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

SqlFiddleDemo

输出：

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

Answer 2

DEMO

首先找到的最后一个索引 ' - '

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

然后将解压后的左侧部分 -

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