I have following data in my table "devices" … I executed below query … It returns result given below … How to come out of this so that it should ignore NULL AND result should be …
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 a table with three fields, FirstName, LastName and Email. Here's some dummy data: … Now, if I do: … Vitals for Joe is null, as there is a single null field. How do you overcome this behaviour?
If I have the table … This will display Firstname-Middlename-Surname e.g. … The second one (Jane’s) displays correct, however since John doesn’t have a middlename, I want it to ignore the second dash.
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.
What is the difference between … and … and why does the latter not work?
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null
SELECT header, txt FROM news UNION ALL SELECT name, pass FROM members This will combine results from both news table and members table and return all of them. Another Example: ' UNION SELECT 1, 'anotheruser', 'doesnt matter', 1--. UNION – Fixing Language Issues.
Note: A NULL value is different from a zero value or a field that contains spaces.
Даже выражение NULL != NULL не будет истинным, ведь нельзя однозначно сравнить одну неизвестность с другой. Кстати, ложным это выражение тоже не будет, потому что при вычислении условий Oracle не ограничивается состояниями ИСТИНА и ЛОЖЬ.