要在列中存储逗号分隔的值是错误的设计，您应该查看 数据库规范化 ，并通过将所有相关的type_head存储在联结表中来规范化您的结构，但是如果您无法更改结构，那么在mysql中您可以使用 FIND_IN_SET() 并加入您的c_head表，如果它在提供的集合中找到值，它将选择记录，IN()对集合或逗号分隔列表中的值不起作用

To store comma separated values in column is bad design you should look at Database Normalization and do normalize your structure by storing all related type_head in a junction table,but if you can't change structure so in mysql you can use FIND_IN_SET() and join your c_head table,it will select records if it find the value in provided set,IN() will not work for values in set or in comma separated list

SELECT i.id, i.item 
FROM c_item i
JOIN c_head h ON(FIND_IN_SET(i.type_head,h.no) > 0)
WHERE h.id = 9
ORDER BY i.item