Within a query, tables or subqueries may be aliased for readability and so that the same table can be referenced more than once in the query with different join conditions.
6
votes
3answers
88 views
Is using SUM() twice suboptimal?
I know I have to write SUM twice, if I wish to use it in a HAVING clause (or use a derived table otherwise):
SELECT id,
sum(hours) AS totalhours
FROM mytable
GROUP BY id
HAVING sum(hours) ...
0
votes
2answers
68 views
Multiple Aliases in an SQL Query
Would it be possible to give a table in MySQL query multiple aliases?
If so how would I do this?
0
votes
0answers
27 views
Connector Table Hash Values using alias
I am designing a system which stores certain hash values to represent certain pieces of text for example.
Each hash value can represent more than one text file.
I have 4 tables being the ...
4
votes
1answer
152 views
Besides attaching the debugger, is there any other differences between “(local)\Instance” and “MyLocalName\Instance”?
When using SQL Server Management Studio for SQL Server 2008 R2 connecting to a local SQL Server 2008 R2 instance (version 10.50.2500), I know that if I am using the instance name (local)\sql2008 it ...
9
votes
2answers
566 views
Why are queries parsed in such a way that disallows the use of column aliases in most clauses?
While trying to write a query, I found out (the hard way) that SQL Server parses WHEREs in a query long before parsing the SELECTs when executing a query.
The MSDN docs say that the general logical ...
2
votes
1answer
118 views
Alias Names and Two Table Query Problems
I'm quite new to querying databases, I've only been doing it for about 2 weeks in the current job that I'm in and have never touched SQL prior to this.
I'm working on trying to use alias names to ...
7
votes
2answers
1k views
Subqueries' aliases same as main queries' aliases
I have an SQL query whose aliases are the same as some of its subquery's aliases.
For example:
select *
from ROOM r
where ...
(
select *
from ROAD r
...
