MySQL is a special condition. The string is divided by 0 results.

SELECT * Form user where username = '/1;

At first, I thought it was the wrong grammar ....

Results come out a bunch of results.

The original condition is ' divide by 1 '

"What's the result of dividing by 1?"

It turns out that there is an implicit conversion in MySQL (priority conversion)

String conversion Result:

' ABC ' converted to 0

' 25a ' converted to 25

' 123 ' converted to 123

"is also a string so convert to 0

"/1 equals 0/1 so 0 divided by 1 equals 0.

Similarly: The username field is 0 as long as it is a pure string.

so The result of username = '/1 is: as long as the username is a pure string, it will appear in the result.

PS: Think select * Form user where username = '/0;

xdjg5rcuhd7gemxjaaybgctjnjjkjdlubd6excqvcrglpzmlufk50ib9qyimpsi7qy5e1jm8s8exfbsigrg9xyaelhptltscba+ if7wradvanrgt5xnvmx8elimajjabcbz9jqfxfxb12salnimrrvrqo1cwdeeitdbrlz6w/kafk8yua5iy25/+cpylqdd2efejgjz4ysjgqqtp+ vjeknds/ Mgsgnhdoulfeglovfscjfnhkgmpw79tgwzhjrqbzof4bcgxj9uvsvvikcwuc6elcv95kbckt7x44sp3xzqope4oqfqhgzkrmtoynww2ogvfrsorec2wjg +dpfcl3fzanjfvfjvew9+d/it+ykdjexzbmv2xusrq3+nynr/eklvmoy1x4km=

MySQL is a special condition. The string is divided by the result of 0.