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
select a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f
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...
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..?
Different ways to replace NULL in sql server - Part 15 - Продолжительность: 11:42 kudvenkat 257 102 ��росмотра.
Sql Injection Using Null Query (Oracle injection).
NULL is a special value that signifies 'no value'. Comparing a column to NULL using the = operator is undefined. Instead, use WHERE IS NULL or WHERE IS NOT NULL. The definitive guide for data professionals.
-- By default ANSI_NULLS is off so null comparisons follows the SQL-92 standard. - - In future version of SQL Server, it won't be possible to modify this setting.
R language supports several null-able values and it is relatively important to understand how these values behave, when making data pre-processing and data
How to count and retrieve null and not null on same column in MySQL?