MySQL 字符串存储类型比较
1. CHAR
固定长度字符串最大长度为 255 字符存储时右padding空格到指定长度检索时自动删除尾随空格适用于长度固定的短字符串(如邮政编码)
示例:
CREATE TABLE example (id INT, code CHAR(5));
INSERT INTO ex…
Here is the code for you to see directly, however, there are a few points.
1. in the second ‘if’ clause, note the existence of the root node
2. Once there is at least one false value among the serval judgment values, the result after the && ope…