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...
COUNT(expr) will count the number of rows where expr is not null, thus you can count the number of nulls with expressions like these
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько
UNION ALL SELECT NULL, *, NULL, NULL FROM email. I understand what this does and why; the hacker needs to create a query that has the same number
Hours 1 1 2 null null null. The result must be: 3. My query is: select count(distinct hour) from hours; but it returns: 2. I tested also
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
null - Null против False против 0 в PHP - Qaru.
...NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,CONCAT%28version(),0x3a,user
returns non null values in group */ SELECT COUNT(Col1) FROM ##TestData; Because of this, COUNT, DISTINCT, and NULLs have a special relationship with each other
I've been asked about counting NULL values several times so I'm going to blog about it in hopes others will be helped by this explanation of NULL values in