If I have the table … This will display Firstname-Middlename-Surname e.g. … The second one (Jane’s) displays correct, however since John doesn’t have a middlename, I want it to ignore the second dash.
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.
I dont want to return null value, how to check not null or how to make isset cond in query …
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 sum(case when a is null then 1 else 0 end) count_nulls , count(a) count_not_nulls from us; Or
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: mysql> SELECT * FROM my_table WHERE phone = NULL
I'd like to update all NULL fields in one table to 0. Of course … would do the job. But I wonder if there´s a smarter solution than just c&p this line for every column.
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...
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!