Re: Not very good at SQL, trying to query multiple tables

Just a couple of comments;
1. Always bottom post in this group
2. The to_date function should be on the date literal in the where clause because;

• you would need a to_char function to compare with a character string, but even better
• put the to_date function on the literal so that if there is an index on the column, it can be used ex: " and RE.begtime between to_date('2006-07-01','YYYY-MM-DD') and to_date('2006-07-31','YYYY-MM-DD') (or is the RE.begtime not a date type column? - if so, simply change the literal...) 3. You hinted at the table primary and foreign keys with the business logic, but I find that when you combine several tables together, one of the trickiest part is to always ensure that every row combination is properly restricted - to avoid a multiplication factor. You can add a "count(*)" in the select column list to see if the the generated number of rows is in the ballpark of what you would expect. The group by clause will sometime hide such an error, and the only way you would find out is if the sum(ro.rollwidth) was some unrealistic number.

extra 2 cents Received on Tue Aug 01 2006 - 11:54:16 CDT