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 have developed a query, and in the results for the first three columns I get NULL. How can I replace it with 0?
In postgres, I'm getting an error when I try to union two tables where one table has a column (Amount) containing double precision data type...
select cast (2000 as type of quint) from rdb$database select cast (2000 as int) from rdb$database.
What is the difference between … and … and why does the latter not work?
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as
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..?
Note: A NULL value is different from a zero value or a field that contains spaces.
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct comparison operators.
Специальное значение NULL означает отсутствие данных, констатацию того факта, что значение неизвестно. По умолчанию это значение могут принимать столбцы и переменные любых типов, если только на них не наложено ограничение NOT NULL.