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 a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f from table3.
UNION ALL SELECT NULL, *, NULL, NULL FROM email. I understand what this does and why; the hacker needs to create a query that has the same number of columns as the query it's being merged with, and shifted around the * to make sure the emails are displayed. That's not my question.
1' UNION SELECT @--+ #The used SELECT statements have a different number of columns 1' UNION SELECT @,@--+ #The used
CONCAT_NULL_YIELDS_NULL ON INSERT INTO Mytable(StringValue) SELECT COALESCE
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.
sql injection "union select null" - CodeProject | To display as.
SELECT * FROM schedule WHERE IS NOT NULL.
If a null pointer constant is converted to a pointer type, the resulting pointer, called a null pointer, is guaranteed to compare unequal to a pointer to any object or function.”
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.