I have following data in my table "devices" … I executed below query … It returns result given below … How to come out of this so that it should ignore NULL AND result should be …
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..?
mysql> SELECT NULL, 1+NULL, CONCAT('Invisible',NULL); To search for column values that are NULL, you cannot use an expr = NULL test. The following statement returns no rows, because expr = NULL is never true for any expression: Press CTRL+C to copy. mysql> SELECT * FROM my_table...
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
Например, SELECT 'abc' + NULL дает в результате NULL.For example, SELECT 'abc' + NULL yields NULL. Когда параметр SET CONCAT_NULL_YIELDS_NULL установлен в значение OFF, объединение значения NULL со строкой дает в результате исходную строку (значение NULL...
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...
If I have this - tadd is the Address table: … Is there a way to exclude the apt_number if it doesn't exist? I was thinking of: … But it will return only those rows with apt_number...
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct comparison operators.
NULL is special in SQL. NULL indicates that the data is unknown, inapplicable or even does not exist. In other words, NULL represents that the data is missing in the database. For example, if an employee does not have any phone number, you can store it as an empty string.
> select f.name, group_concat(quality) quality, sum(fs.quantity) quantity, sum(fp.price*fs.quantity) price from (select * from fruits where name = 'apple') as f, fruitstock as fs