MySQL query to count non-null values in a single row
I'm trying to put together a MYSQL query that will count the number of Non-Null (or better yet, non-zero) values in select fields in a single row and then sort from lowest to highest (based on the count). For example, I have a table with 5 fields... ID, Name, Score_1, Score_2, Score_3. I want to count how many times the value "0" exists in Score_1, Score_2 and Score_3 for each record, then sort from most non zero values to least.
ID Name Score_1 Score_2 Score_3 1 Dan 8 7 0 2 Joe 0 0 3 3 Chris 0 0 0 4 Mike 4 5 5
I assume the query has to look something like this...
Select ID, Name, Score_1, Score_2, Score_3 where (???) ORDER BY (???)
Output should l开发者_如何学编程ook like this (ID 4 is displayed first since it has the least amount of non-zero entries)...
ID Name Score_1 Score_2 Score_3 4 Mike 4 5 5 1 Dan 8 7 0 2 Joe 0 0 3 3 Chris 0 0 0
I'm somewhat new to mysql query's, so any help would be greatly appreciated. I thought the COUNT function would help, but that function appears to count columns from all rows. Perhaps there is a way to use the COUNT function and limit it to a singel row so it can be sorted by that row count?
This should do what you want:
SELECT ID, Name, Score_1, Score_2, Score_3
FROM Table1
ORDER BY (Score_1 = 0) + (Score_2 = 0) + (Score_3 = 0)
Result:
ID Name Score_1 Score_2 Score_3 4 Mike 4 5 5 1 Dan 8 7 0 2 Joe 0 0 3 3 Chris 0 0 0
try This:
Select id, Count1, Count2, Count3, Count4
From
(Select
Sum(Case When IsNull(Score_1,0) = 0 Then 1 Else 0 End) Count1,
Sum(Case When IsNull(Score_2,0) = 0 Then 1 Else 0 End) Count2,
Sum(Case When IsNull(Score_3,0) = 0 Then 1 Else 0 End) Count3,
Sum(Case When IsNull(Score_4,0) = 0 Then 1 Else 0 End) Count4
From Table
Group By Id) Z -- This column (Id) better not be the PK for this table!!!
Order By Count1 + Count2 + Count3 + Count4
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