Generating table with SUM columns based on different conditions - mysql

Question

I am fairly new to SQL and I am struggling with generating a table with multiple aggregates based on certain filters.
My temporary able has 3 columns where an individual is unique by Category ID AND Customer ID (i.e. there can be multiple identical Customer IDs across categories).
Category ID
Customer ID
Number of Purchases
X
A
4
X
B
10
X
C
2
Y
A
2
Y
E
6
Z
A
10
Z
C
5
Z
D
7
The output table I am looking for is basically 4 columns: grouped by category ID identifying total number of customers who have at least 3 purchases, customers who have at least 5 purchases as well as total purchases across all customers within that category. The output table would look like this:
Category_ID
Total_Customers_3
Total_Customers_5
Total_Purchases
X
2
1
16
Y
1
1
8
Z
3
3
22
When I input the following code, I get the correct total purchases column per category but the total number of customers who had at least 3 purchases per category is incorrect as the aggregates are identical across all categories.
My code:
SELECT table.categoryID AS Category_ID
(SELECT COUNT (table.customerID)
FROM table
WHERE table.purchases >=3) AS Total_Customers_3,
(SELECT COUNT (table.customerID)
FROM table
WHERE table.purchases >=5) AS Total_Customers_5,
SUM (table.purchases) AS Total_Purchases,
FROM table
GROUP BY Category_ID, Total_Customers_3, Total_Customers_5,
(P.S When I try to just GROUP BY Category_ID, I get an ERROR that syntax is incorrect because I have sub-queries in my SELECT statement.
The incorrect table (i.e. same number of total customers meeting the condition across all categories) I get looks like:
Category_ID
Total_Customers_3
Total_Customers_5
Total_Purchases
X
2
1
16
Y
2
1
8
Z
2
1
22
Update: I should have included this in the original question but I am actually looking to generate 2 columns in the same about total number of customers based on 2 conditions - one for customers with at least 3 purchases and another column for customers with at least 5 customers.

Answer 1

Aggregate by category, and the use conditional aggregation to get the counts and totals.
SELECT
Category_ID,
SUM(purchases >= 3) Total_Customers_3,
SUM(CASE WHEN purchases >= 3 THEN purchases ELSE 0 END) AS Num_Purchases_3,
SUM(purchases >= 5) Total_Customers_5,
SUM(CASE WHEN purchases >= 5 THEN purchases ELSE 0 END) AS Num_Purchases_5
FROM yourTable
GROUP BY Category_ID;
Demo