sql - Union to handle NULL values - Stack Overflow
As shown below, I need not null values to be at the start of all output fields.
Confusing SQL error in SELECT NULL, *, NULL, NULL - Stack Overflow
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.
sql - CONCAT'ing NULL fields - Stack Overflow | Post as a guest
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?
SQL using If Not Null on a Concatenation - Stack Overflow
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.
SQL Server String Concatenation with Null - Stack Overflow
I am creating a computed column across fields of which some are potentially null. The problem is that if any of those fields is null, the entire computed column will be null.
sql injection "union select null" - CodeProject | To display as
Union select null, null, null, null, null, null, null from information_schema.tables.
SQL is null and = null - Stack Overflow
What is the difference between … and … and why does the latter not work?
SQL NULL Values - IS NULL and IS NOT NULL
Note: A NULL value is different from a zero value or a field that contains spaces.
NULL (SQL) — Википедия
NULL в Системах управления базами данных (СУБД) — специальное значение (псевдозначение), которое может быть записано в поле таблицы базы данных (БД). NULL соответствует понятию «пустое поле», то есть «поле, не содержащее никакого значения».
Заметка про NULL / Хабр
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.