Question

I asked a question earlier about extracting data from two table and got a beautiful answer which worked perfectly by I asked a question earlier about extracting data from two table and got a beautiful answer which worked perfectly by Ollie Jones

Here is the new situation
I want to get a certain data from the first table by adding a WHERE but now it fails and it seems as if it should not

This query does just fine when performing this function

table 1       table 2

product 1     product 4
product 2     product 2
product 3
product 4


SELECT ifnull( b.number >0, 0 ) purchased
FROM 1androidProducts a
LEFT JOIN (
   SELECT count( * ) number, product
   FROM 1androidSales 
   WHERE udid = '' 
   GROUP BY product
) b 
ON a.appTitle = b.product
ORDER BY a.appTitle
LIMIT 0 , 30

yields this result

result 

0
1
0
1

in short
for every item in table 1 shows this

a 0 if the table-1-item does not appear in table two
–OR–
a 1 if table-1-item does show in table 2

Now when I add this line

SELECT ifnull( b.number >0, 0 ) purchased
FROM 1androidProducts a
WHERE a.accountID = 2        <<---------- I added this line 
LEFT JOIN (
   SELECT count( * ) number, product
   FROM 1androidSales 
   WHERE udid = ''
   AND accountID = 2          <<---------- I added this line
   GROUP BY product
) b 
ON a.appTitle = b.product
ORDER BY a.appTitle
LIMIT 0 , 30

It now gives an error

1064 – You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘LEFT JOIN ( SELECT count( * ) number, product FROM 1androidSales ‘ at line 4

I simply want to get a subset of table 1 based on the accountID to compare against the second table.

so if I had this

         table 1            table 2

accountid =1  product 1     accountid =2  product 4
accountid =1  product 2     accountid =2  product 2
accountid =1  product 3     accountid =2  product 5
accountid =1  product 4
accountid =2  product 1     
accountid =2  product 2
accountid =2  product 3
accountid =2  product 4
accountid =2  product 5

would yield this result

result 

0
1
0
1
1

so the total number result records matches the amount of records in table one that meet the accountID value of 2

I thought this would be an easy change but it is messing me up big time

Thanks for your time

Answer 1

I believe you have your first where clause in the wrong spot, put it after the join:

SELECT ifnull( b.number >0, 0 ) purchased
FROM 1androidProducts a
LEFT JOIN (
   SELECT count( * ) number, product
   FROM 1androidSales 
   WHERE udid = ''
   AND accountID = 2 
   GROUP BY product
) b 
ON a.appTitle = b.product
WHERE a.accountID = 2 --Moved the first where clause
ORDER BY a.appTitle
LIMIT 0 , 30