SQL-voorwaarde op vensterfunctie

Alles-in-een bewerking:

En geweldig hoofdstuk Impact op vensterfuncties :

Stel je hebt:

CREATE TABLE Test ( Id INT) ;
 
INSERT  INTO Test VALUES  ( 1001 ), ( 1002 ) ;

SELECT Id
FROM Test
WHERE Id = 1002
  AND ROW_NUMBER() OVER(ORDER BY Id) = 1;

Geval 1:

If ( Id = 1002 ) is first, then if ( ROW_NUMBER() OVER(ORDER BY Id) = 1 )

Resultaat:1002

Geval 2:

If ( ROW_NUMBER() OVER(ORDER BY Id) = 1 ), then check if ( Id = 1002 )

Resultaat:leeg

Om te krijgen wat je wilt, kun je de vensterfunctie inpakken met CTE/subquery zoals in Gordon antwoord :

;WITH cte AS
(
  SELECT t.*, MAX(AVG) OVER (PARTITION BY city) AS average
  FROM avgTemperatures t
)
SELECT *
FROM cte
where average > 19
ORDER BY id;

db<>fiddle-demo

Uitgang:

╔═════╦══════════╦═════╦═════════╗
║ id  ║   city   ║ avg ║ months  ║
╠═════╬══════════╬═════╬═════════╣
║   1 ║ New-York ║  20 ║     3   ║
║   2 ║ New-York ║  19 ║     6   ║
║   3 ║ New-York ║  15 ║    12   ║
║   4 ║ New-York ║  15 ║    24   ║
║  11 ║ Miami    ║  28 ║     1   ║
║  12 ║ Miami    ║  25 ║     4   ║
║  13 ║ Miami    ║  21 ║    12   ║
║  14 ║ Miami    ║  22 ║    15   ║
║  15 ║ Miami    ║  20 ║    24   ║
╚═════╩══════════╩═════╩═════════╝