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.
select cast (2000 as type of quint) from rdb$database select cast (2000 as int) from rdb$database. If TYPE OF is used with a (VAR)CHAR type, its character.
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...
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null
Note: A NULL value is different from a zero value or a field that contains spaces.
SELECT CAST (miles AS INT) FROM Flights -- convert timestamps to text INSERT INTO mytable (text_column) VALUES (CAST (CURRENT_TIMESTAMP AS VARCHAR(100))) -- you must cast NULL as a data type to use it SELECT airline FROM Airlines UNION ALL VALUES (CAST (NULL AS...
Оператор объединения с NULL ?? возвращает значение своего операнда слева, если его значение не равно null.
Null values can be used as a condition in the WHERE and HAVING clauses. For example, a WHERE clause can specify a column that, for some rows, contains a null value. A basic comparison predicate using a column that contains null values does not select a row that has a null value for the column.
This C# article examines the null coalescing operator. It tests the performance of this operator.
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.