Good Evening, Good Morning Wherever you are whenever you may be reading this.
I am new to this email group and have some good experience with SQL and PostgreSQL database. I am currently working on a PHP / PostgreSQL project and I came upon something I could not figure out in SQL. I was wondering if anyone here could take a look and perhaps offer some guidance or assistance in helping me write this SQL query.
Please Consider the following information: ------------------------------------------- I have a postgresql table called 'inventory' that includes two fields: 'model' which is a character varying field and 'modified' which is a timestamp field. So the table inventory looks something like this: model modified ------------- ---------- I778288176 2010-02-01 08:27:00 I778288176 2010-01-31 11:23:00 I778288176 2010-01-29 10:46:00 JKLM112345 2010-02-01 08:25:00 JKLM112345 2010-01-31 09:52:00 JKLM112345 2010-01-28 09:44:00 X22TUNM765 2010-01-17 10:13:00 V8893456T6 2010-01-01 09:17:00
Now with the table, fields and data in mind look at the following three queries: SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-02-01'; SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-01-20'; SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-01-01'; All three of the above queries work and provide results. However, I want to combine the three into one SQL Statement that hits the database one time. How can I do this in one SQL Statement? Is it possible with sub select? Here is what result I am looking for from one SELECT statement using the data example from above: count1 | count2 | count3 ------------------------------- 2 2 4 Can this be done with ONE SQL STATEMENT? touching the database only ONE time?
Please let me know. Thanx> :) NEiL |