Solution: $str="QB".str_pad(($maxid[0]["max(id)"]+1),5,"0",STR_PAD_LEFT );
where $maxid[0 ]["max(id)"]+1) is to use the max function to find the value with the largest ID from the database. The ID is the primary key and will not be repeated.
str_pad() function pads a string to the specified length.
Grammar
str_pad(string,length,pad_string,pad_type)
Copy after login
| Parameters |
Description |
| string |
Required. Specifies the string to be filled. |
| length |
Required. Specifies the length of the new string. If the value is less than the length of the original string, no operation is performed. |
| pad_string |
Optional. Specifies the string used for padding. The default is blank. |
| pad_type |
Optional. Specifies the side of the padding string. Possible values:
| 参数 |
描述 |
| string |
必需。规定要填充的字符串。 |
| length |
必需。规定新字符串的长度。如果该值小于原始字符串的长度，则不进行任何操作。 |
| pad_string |
可选。规定供填充使用的字符串。默认是空白。 |
| pad_type |
可选。规定填充字符串的那边。可能的值：
- STR_PAD_BOTH – 填充到字符串的两头。如果不是偶数，则右侧获得额外的填充。
- STR_PAD_LEFT – 填充到字符串的左侧。
- STR_PAD_RIGHT – 填充到字符串的右侧。这是默认的。
|
- STR_PAD_BOTH – Pad to both ends of the string. If it's not an even number, the right side gets extra padding.
- STR_PAD_LEFT – Pad to the left side of the string.
- STR_PAD_RIGHT – Pad to the right side of the string. This is the default.
|
http://www.bkjia.com/PHPjc/313501.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/313501.htmlTechArticleSolution: $str="QB".str_pad(($maxid[0]["max(id) "]+1),5,"0",STR_PAD_LEFT ); where $maxid[0]["max(id)"]+1) is to use the max function to find the value with the largest ID from the database,...
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
