Summarize tables with percent of sum in single query - sql

Question

I have an ACTIVE_TRANSPORTATION table:
+--------+----------+--------+
| ATN_ID | TYPE | LENGTH |
+--------+----------+--------+
| 1 | SIDEWALK | 20.6 |
| 2 | SIDEWALK | 30.1 |
| 3 | TRAIL | 15.9 |
| 4 | TRAIL | 40.4 |
| 5 | SIDEWALK | 35.2 |
| 6 | TRAIL | 50.5 |
+--------+----------+--------+
It is related to an INSPECTION table via the ATN_ID:
+---------+--------+------------------+
| INSP_ID | ATN_ID | LENGTH_INSPECTED |
+---------+--------+------------------+
| 101 | 2 | 15.2 |
| 102 | 3 | 5.4 |
| 103 | 5 | 15.9 |
| 104 | 6 | 20.1 |
+---------+--------+------------------+
I want to summarize the information like this:
+----------+--------+-------------------+
| TYPE | LENGTH | PERCENT_INSPECTED |
+----------+--------+-------------------+
| SIDEWALK | 85.9 | 36% |
| TRAIL | 106.8 | 23% |
+----------+--------+-------------------+
How can I do this within a single query?

Answer 1

Here is the updated answer using ACCESS 2010. Note that LENGTH is reserved in ACCESS, so it needs to be changed to LENGTH_
SELECT
TYPE,
SUM(LENGTH) as LENGTH_,
SUM(IIF(ISNULL(LENGTH_INSPECTED),0, LENGTH_INSPECTED))/SUM(LENGTH) as PERCENT_INSPECTED
FROM
ACTIVE_TRANSPORTATION A
LEFT JOIN INSPECTION B
ON A.ATN_ID = B.ATN_ID
GROUP BY TYPE
Here is the answer using T-SQL in SQL SERVER 2014 I had originally
SELECT SUM(LENGTH) as LENGTH,
SUM(ISNULL(LENGTH_INSPECTED,0))/SUM(LENGTH) as PERCENT_INSPECTED,
TYPE
FROM
ACTIVE_TRANSPORTATION A
LEFT JOIN INSPECTION B
ON A.ATN_ID = B.ATN_ID
GROUP BY TYPE
Let me know if you need it to be converted to percent, rounded, etc, but I'm guessing that part is easy for you.