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...
Необходимые условия для операторов union и union all.
Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. Объединение UNION и UNION ALL в SQL – описание и примеры.
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.
11223344) UNION SELECT NULL,NULL,NULL,NULL WHERE 1=2 –- Если нет ошибки, значит синтаксис верный, т.е. используется MS SQL Server.
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Spatu union all select null null null null-- oevz.
The IS NULL operator is used to test for empty values (NULL values). The following SQL lists all customers with a NULL value in the "Address" field: Example. SELECT CustomerName, ContactName, Address FROM Customers WHERE Address IS NULL
The UNION ALL operator is employed to combine the results of 2 select statements as well as duplicate rows. The same rules that apply to the
Пустые значения(NULL) запрещены с ограничением NOT NULL, которое будет обсуждаться в Главе 18. Кроме того, вы не можете использовать UNION в под- запросах, а также не можете использовать агрегатные функции в предложении SELECT запроса в объединении.