select a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f from table3.
I have come across some code that says … What exactly is this doing? Is it getting the field names unitcost and markup? Why would you use "select null as..."? New to this sorry. Thanks.
The Background I was trying to solve the fourth realistic mission in hackthissite.org, and couldn't figure out exactly what SQL I should inject into the URL to retrieve the list of emails.
Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as
What is the difference between … and … and why does the latter not work?
I am working on a UNION ALL and receive this error to start: Msg 205, Level 16, State 1, Line 1 All queries combined using a UNION...
Note: A NULL value is different from a zero value or a field that contains spaces.
Number of null-s on change between passed and failed queries is the one attacker looks for. 4) Same for user auth tables: ends query with likely non-existent ID then inspects number of columns. null-s are replaced by HEX values. 5) misguiding auth check by injecting crafted $user into query PHP string like.
NULL is special in SQL. NULL indicates that the data is unknown, inapplicable or even does not