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 null, 'Actual null' from dual union all select '', 'Null string' from dual union all select ' ', 'Single space' from dual union all
Note: A NULL value is different from a zero value or a field that contains spaces.
How can I run a MySQL query that selects everything that is not null? It would be something like … Do I just remove the all and go..?
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...
Is there a way to set a char variable to 0 or null or something so that it will basically reset my control variable.
The IS NOT NULL condition is used in SQL to test for a non-NULL value.
that's wrong though. (char*)NULL isn't a string at all, it's a null pointer. this isn't a string either even though it's an array of char.
NULL handling in the Oracle database is even more special.
R language supports several null-able values and it is relatively important to understand how these