HAVING-clausule

Van toepassing op: Databricks SQL Databricks Runtime

Filtert de resultaten die worden geproduceerd door GROUP BY op basis van de opgegeven voorwaarde. Vaak gebruikt in combinatie met een GROUP BY clausule.

Syntaxis

HAVING boolean_expression

Parameterwaarden

• boolean_expression

  Elke expressie die resulteert in een resultaattype BOOLEAN. Twee of meer expressies kunnen worden gecombineerd met behulp van logische operatoren zoals AND of OR .

  De expressies die in de HAVING component zijn opgegeven, kunnen alleen verwijzen naar:

  • Constante expressies
  • Expressies die worden weergegeven in GROUP BY
  • Statistische functies

Voorbeelden

> CREATE TABLE dealer (id INT, city STRING, car_model STRING, quantity INT);
> INSERT INTO dealer VALUES
    (100, 'Fremont' , 'Honda Civic' , 10),
    (100, 'Fremont' , 'Honda Accord', 15),
    (100, 'Fremont' , 'Honda CRV'   , 7),
    (200, 'Dublin'  , 'Honda Civic' , 20),
    (200, 'Dublin'  , 'Honda Accord', 10),
    (200, 'Dublin'  , 'Honda CRV'   , 3),
    (300, 'San Jose', 'Honda Civic' , 5),
    (300, 'San Jose', 'Honda Accord', 8);

-- `HAVING` clause referring to column in `GROUP BY`.
> SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING city = 'Fremont';
  Fremont  32

-- `HAVING` clause referring to aggregate function.
> SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING sum(quantity) > 15;
  Dublin  33
 Fremont  32

-- `HAVING` clause referring to aggregate function by its alias.
> SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING sum > 15;
  Dublin  33
 Fremont  32

-- `HAVING` clause referring to a different aggregate function than what is present in
-- `SELECT` list.
> SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING max(quantity) > 15;
 Dublin  33

-- `HAVING` clause referring to constant expression.
> SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING 1 > 0 ORDER BY city;
   Dublin  33
  Fremont  32
 San Jose  13

-- `HAVING` clause without a `GROUP BY` clause.
> SELECT sum(quantity) AS sum FROM dealer HAVING sum(quantity) > 10;
  78

Verwante artikelen:

• GROUP BY
• QUALIFY
• SELECT