Question

I’ve table like this VB(name char(25), amount numeric(6), ret_date date):

Name  Amount  Ret_date
----  ------  --------
abc    500    2011-01-21
def    200    2011-01-20
ghi   1000    
xyz    800    2011-01-22
def    200    
def    400    2011-02-01
pqr   2100    2011-02-12  
abc   3000    
abc   4100
xyz    700    2011-01-22

What I wanted is (count based on ret_date for distinct names: total count, return count, pending count):

Name    tc  rc  pc 
abc     3   1   2 
def     3   2   1 
xyz     2   2   0 
ghi     1   0   1 
pqr     1   1   0

I’ve tried the following queries, nothing worked!

SELECT vb.name, COUNT(*) tc, r.rc, p.pc FROM vb, ;
 (SELECT name, COUNT(*) rc FROM vb WHERE ret_date != {} group BY name) r, ;
 (SELECT name, COUNT(*) pc FROM vb WHERE ret_date = {} group BY name) p ;
 GROUP BY vb.name ORDER BY tc desc
SELECT vb.name, COUNT(*) tc, r.rc, p.pc FROM vb ;
  LEFT JOIN (select name, COUNT(*) rc FROM vb WHERE ret_date != {} group BY name) r ON r.name = vb.name ;
  LEFT JOIN (select name, COUNT(*) pc FROM vb WHERE ret_date = {} group BY name) p ON p.name = vb.name ;
  GROUP BY vb.name
SELECT vb.name, COUNT(*) tc, r.rc, p.pc FROM vb ;
  LEFT JOIN (select r.name, COUNT(*) rc FROM vb r WHERE ret_date != {} group BY name) r ON r.name = vb.name ;
  LEFT JOIN (select p.name, COUNT(*) pc FROM vb p WHERE ret_date = {} group BY name) p ON p.name = vb.name ;
  GROUP BY vb.name

I was able to get the count with 3 separate queries (total count, count for ret_date = {}, ret_date != {}) but can’t get at the same time using a single query. Please help me get the desired output. I am new to SQL and can understand the basics but things like joins, subqueries are still difficult to understand! It would be helpful if you could explain what your query does.

Note: I’m using MS Visual Foxpro 9.0 (Windows 7). { } is a notation used to express emptiness for date type in Foxpro and != is not equal to operator.

Thanks a lot.

Answer 1

SELECT name, COUNT(DISTINCT name) as uc, COUNT(*) as tc, SUM(IF(ret_date IS NULL, 0, 1)) as rc, SUM(IF(ret_date IS NOT NULL, 0, 1)) as pc
FROM vb
GROUP BY name;

I don’t have access to Foxpro, but this works in MySQL. Hopefully you can tweak it to suit your purposes.