当同一表的另一列中存在多于1个不同值时，用于从一列中计算不同值的SQL查询

Question

I have a single table called "Vehicle" that contains a column with unique VehicleId's. On this same "Vehicle" table I also have a column for QuoteId's.

I need to create a SQL query that returns how many distinct QuoteId's were obtained with more than one distinct VehicleId. In other words, I'm trying to determine a count of how many quotes had more than one vehicle on them.

I have searched all over for this information and come up with a basic text statement to try and help me figure this out:

"Select the count of distinct QuoteId's that have multiple distinct VehicleId's"

I am unable to come up with a way to get this to work but have included an example of what I am attempting to accomplish to try and clarify:

SELECT COUNT(DISTINCT QuoteId's) AS 'Multi Vehicle Quotes'
From Vehicle
WHERE VehicleId = DISTINCT VehicleId > 1

Any help or advice would be greatly appreciated!

Answer 1

I think you are very close there. You need to first find quotes with more than one vehicle and store that in a CTE. Then count the number of quotes from the CTE.

With CTE as (
SELECT (
 VehicleID
 ,COUNT(DISTINCT Quotes)
FROM Vehicle
HAVING COUNT(DISTINCT Quotes) > 1)

SELECT COUNT(VehicleID) as MultiVehicleQuotes
FROM CTE

Answer 2

You need nested aggregation:

select count(*)
from
 (
   SELECT QuoteId
   From Vehicle
   group by QuoteId
   having count(DISTINCT VehicleId) > 1
 ) as dt

Instead of COUNT(DISTINCT) > 1 which is expensive you can also use

having min(VehicleId) <> max(VehicleId)

Answer 3

这是一个查询，它将帮助您实现所需的目标。

 SELECT DISTINCT vehicleId, qouteId,count(qouteId) as vehicleCountForQouteId FROM Vehicle GROUP BY qouteId

Answer 4

Let's assume this is the data on your vechicle table:

SELECT * FROM vehicle ORDER BY vehicle_id ;

vehicle_id | quote_id
---------: | -------:
         1 |      100
         2 |      100
         3 |      100
         4 |      101
         5 |      102
         6 |      102
         7 |      103

Your first step would be to get the list of quote_id , and how many there are of each. Since, in the previous table, vehicle_id is unique, you just need:

SELECT
    quote_id, count(*) AS number_of_vehicles_quoted
FROM
    vehicle 
GROUP BY
    quote_id ;

quote_id | number_of_vehicles_quoted
-------: | ------------------------:
     100 |                         3
     101 |                         1
     102 |                         2
     103 |                         1

Second step : from the previous query, you want only those with number_of_vehicles_quoted > 1. That can be done with a HAVING clause after the GROUP BY , which places a further restriction on the GROUP ed rows.

SELECT
    quote_id, 
    count(*) AS number_of_vehicles_quoted
FROM
    vehicle 
GROUP BY
    quote_id 
HAVING
    count(*) > 1 ;

quote_id | number_of_vehicles_quoted
-------: | ------------------------:
     100 |                         3
     102 |                         2

If you don't like HAVING , or don't feel comfortable with it, you can wrap the query with another one, and do:

SELECT
    quote_id, number_of_vehicles_quoted
FROM
    (SELECT
        quote_id, 
        count(*) AS number_of_vehicles_quoted
    FROM
        vehicle 
    GROUP BY
        quote_id 
    ) AS q
WHERE 
    number_of_vehicles_quoted > 1 ;

Third step : finally, count(*) the number of rows of the previous query:

SELECT
     count(*) AS count_of_quotes_with_more_than_one_vehicle_id
FROM
    (SELECT
        quote_id, 
        count(*) AS number_of_vehicles_quoted
    FROM
        vehicle 
    GROUP BY
        quote_id 
    HAVING
        count(*) > 1
    ) AS quotes_with_more_than_one_vehicle_id ;

| count_of_quotes_with_more_than_one_vehicle_id |
| --------------------------------------------: |
|                                             2 |

You can check the whole setup and the steps at dbfiddle here . The query is plain SQL, and works with all engines available on DBFiddle (except Oracle, which complains about identifiers being too long, and that would work if I weren't so verbose ;-)

---

NOTE 1: you can simplify a bit the last query, since you don't use some of the information on the outermost query. That will speed it up a bit, although not in a significant way:

SELECT
    count(*) AS count_of_quotes_with_more_than_one_vehicle_id
FROM
    (SELECT
        -- quote_id,   -- You actually don't use this one in the outer query
        -- count(*) AS number_of_vehicles_quoted -- This neither
        1
    FROM
        vehicle 
    GROUP BY
        quote_id 
    HAVING
        count(*) > 1
    ) AS quotes_with_more_than_one_vehicle_id ;

dbfiddle here

---

NOTE 2: If your vehicle_id s were not guaranteed to be unique, you'd use:

SELECT
    count(*) AS count_of_quotes_with_more_than_one_vehicle_id
FROM
    (SELECT
        1
    FROM
        vehicle 
    GROUP BY
        quote_id 
    HAVING
        count(DISTINCT vehicle_id) > 1
    ) AS quotes_with_more_than_one_vehicle_id ;

Answer 5

Here, try this:

SELECT    COUNT(a.QuoteID)  AS 'Count', 
          a.QuoteID         AS 'QuoteID'
FROM      Problems.Vehicle  AS a
GROUP BY  a.QuoteID
HAVING    COUNT(a.QuoteID)  > 1

NOTE: Problems.Vehicle is the name of the schema the table is in and the name of the table.