Question

I have table with following structure

id         int             auto increment, primary key
uid        int             (comment: userid)
cdt        date/time       (comment: current date)
hits       int             (comment: no. of hits)

Now, I need a query such as

for a particular combination of ‘uid’ and ‘cdt’, if there is row available, then update hits (ie., add 1 to hits) otherwise add new row with ‘uid’ and ‘cdt’ values, and hits set to 1

Let me clear further with example

say uid = 01, and cdt = 2010-01-01, if this combination of uid and cdt is not available in table, then new row should be inserted, otherwise value of hits should be update

How to achieve this?

Answer 1

You could do this in two steps:

First:
Query db to know if that particular record is present:

SELECT id FROM your_table 
WHERE uid = your_user_id AND cdt = your_date 

Second:
If previous query returns zero rows:

INSERT INTO your_table
(uid, cdt, hits)
SELECT your_user_id, your_date, 1

else:

UPDATE your_table
SET hits = hits + 1
WHERE uid = your_user_id AND cdt = your_date