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...
select cast (2000 as type of quint) from rdb$database select cast (2000 as int) from rdb$database.
Yes, by using COALESCE. SELECT COALESCE(null_column, 0) AS null_column FROM whatever; COALESCE goes through the list of values you give it, and returns the first non-null value.
SELECT journey.id, null AS departure, TIME_FORMAT(ADDTIME(journey.departure, SEC_TO_TIME(SUM(l1.elapsed))), '%H:%i') AS arrival FROM
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null
In general, every NULL value is taken into account to vary from each alternative NULL in the database.
i am trying to do union i get data with null values and i want do not want it to show in result. such as: column1 col2 col3 col4 col5 col6 test1 1 2 3 null 6 test2 2
Тем не менее, NULL, как NULL-значение, часто используется в SQL. Предположим, появился покупатель, которому еще не назначен продавец. Чтобы констатировать этот факт, нужно ввести значение NULL в поле snum, а реальное значение включить туда позже...
The null character (also null terminator or null byte) is a control character with the value zero. It is present in many character sets, including ISO/IEC 646 (or ASCII), the C0 control code, the Universal Coded Character Set (or Unicode), and EBCDIC.