In postgres, I'm getting an error when I try to union two tables where one table has a column (Amount) containing double precision data type...
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as opt however, I don't want an empty string, I really do need it to be null.
Select char_length(cast('123456789 1' as varchar(10))) from rdb$database. Получаем: Exception ... string truncation Т.е. пробел мы обр��зать можем, а другие символы нет. Так и должно быть или нет?
Ref: 999999.9' union all select 99,2 and '0'='0.
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...
Note: A NULL value is different from a zero value or a field that contains spaces.
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)...
SELECT DISTINCT CAST(EnglishProductName AS char(10)) AS Name, ListPrice FROM dbo.DimProduct WHERE EnglishProductName LIKE 'Long-Sleeve Logo Jersey, M'
Специальное значение NULL означает отсутствие данных, констатацию того факта, что значение неизвестно. По умолчанию это значение могут принимать столбцы и переменные любых типов, если только на них не наложено ограничение NOT NULL.