Select char_length(cast('123456789 1' as varchar(10))) from rdb$database. Получаем: Exception ... string truncation Т.е. пробел мы обрезать можем, а другие символы нет. Так и должно быть или нет?
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.
A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this
The null character (also null terminator or null byte), abbreviated NUL or NULL, is a control character with the value zero. It is present in many character sets, including ISO/IEC 646 (or ASCII)...
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...
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct comparison operators.
Number of null-s on change between passed and failed queries is the one attacker looks for.
Union select null, null, null, null, null, null -- test all nulls --*/ ). A. DECLARE @ColumnDynamicSQL nvarchar(MAX)
5.6 If NULL were defined as follows: #define NULL ((char *)0). wouldn't that make function calls which pass an
In general, R supports: NULL NA NaN Inf / -Inf NULL is an object and is returned when an expression or function results in an undefined value.