I have a set of database tables named like:
site_1_details
site_2_details
site_3_details
...
site_420_details
all tables have the same fields, like:
ID | SETTING | VALUE
----------------------
1 name Site 1 Name
2 desc Site 1 Desc
3 email Site 1 Email...
...
(only the value fields are different)
How can I get a set of values from certain tables?
For example, I want to get the name & email values from sites 3,7 and 15. How could I do that with a SQL query?
SELECT 3 AS siteID, name, email
FROM site_3_details
UNION
SELECT 7 AS siteID, name, email
FROM site_7_details
UNION
SELECT 15 AS siteID, name,email
FROM site_15_details
This is a horribly bad design. Why couldn't you put a "siteID" field into a single table, which'd reduce the query to:
SELECT name, email
FROM site_details
WHERE siteID IN (3,7,15);
comment followup:
Ah well, then you just modify the individual queries:
SELECT 7 AS siteID, ID as fieldID, name AS fieldName
FROM site_7_details WHERE SETTING IN ('name', 'email')
UNION
....
Any reason you've designed the tables like this? Sounds like you're trying to implement your own database on TOP of a database engine which is already perfectly suited to doing this kind of relational data handling.
