Fournir plusieurs critères de jointure à l'aide de l'opérateur conditionnel 'OR' dans Bigquery

Question

Veuillez trouver ci-dessous la requête fournie que je suis capable d'implémenter dans Netezza où, dans le cas où il n'y a pas de jointure sur 'id' alors il cherche la jointure sur la base de «nom». Si l'un des critères est rempli, la jointure externe gauche est effectuée.

Select * from BigqueryTest.colors a 
LEFT JOIN 
BigqueryTest.color2 b 
ON a.id = b.id 
OR a.name = b.name ; 

Cette fonctionnalité ne semble pas être prise en charge dans Bigquery. Je veux dire que je peux fournir plusieurs conditions de jointure avec l'aide de l'opérateur 'AND' mais je ne peux pas utiliser l'opérateur 'OU' qui peut me permettre d'aller de l'avant avec l'opération de jointure même si une seule condition est satisfaite. Toute piste serait appréciée.

Answer 1

... is there any way around to make the code run with 'OR' condition? Because in actual scenario there are more than 100 columns ...

Ci-dessous est une autre option - comme une direction pour vous d'explorer.

#standardSQL 
SELECT a.id AS aid, a.name AS aname, b.id AS bid, b.name AS bname 
FROM (
    SELECT 
     a, IF(matches = 0, STRUCT<id INT64, name STRING>(NULL, NULL), b) AS b 
    FROM (
     SELECT 
      a, b, 
      (a.id = b.id OR a.name = b.name) AS match, 
      COUNTIF(a.id = b.id OR a.name = b.name) 
       OVER(PARTITION BY a.id, a.name) AS matches, 
      ROW_NUMBER() OVER(PARTITION BY a.id, a.name) AS dup 
     FROM `BigqueryTest.colors` AS a 
     CROSS JOIN `BigqueryTest.color2` AS b 
    ) 
    WHERE match OR (matches = 0 AND dup = 1) 
) 
-- ORDER BY a.id 

Vous pouvez tester/jouer avec l'aide des données factices ci-dessous

#standardSQL 
WITH `BigqueryTest.colors` AS (
    SELECT 1 AS id, 'a' AS name UNION ALL 
    SELECT 2 AS id, 'b' AS name UNION ALL 
    SELECT 3 AS id, 'c' AS name 
), 
`BigqueryTest.color2` AS (
    SELECT 1 AS id, 'a' AS name UNION ALL 
    SELECT 11 AS id, 'a' AS name UNION ALL 
    SELECT 2 AS id, 'b' AS name UNION ALL 
    SELECT 2 AS id, 'x' AS name 
) 
SELECT a.id AS aid, a.name AS aname, b.id AS bid, b.name AS bname 
FROM (
    SELECT 
    a, IF(matches = 0, STRUCT<id INT64, name STRING>(NULL, NULL), b) AS b 
    FROM (
    SELECT 
     a, b, 
     (a.id = b.id OR a.name = b.name) AS match, 
     COUNTIF(a.id = b.id OR a.name = b.name) OVER(PARTITION BY a.id, a.name) AS matches, 
     ROW_NUMBER() OVER(PARTITION BY a.id, a.name) AS dup 
    FROM `BigqueryTest.colors` AS a 
    CROSS JOIN `BigqueryTest.color2` AS b 
) 
    WHERE match OR (matches = 0 AND dup = 1) 
) 
ORDER BY a.id 

Answer 2

est ci-dessous pour BigQuery standard SQL

#standardSQL 
SELECT 
    a.id AS aid, a.name AS aname, 
    b.id AS bid, b.name AS bname 
FROM `BigqueryTest.colors` AS a 
LEFT JOIN `BigqueryTest.color2` AS b 
ON a.id = b.id 
UNION DISTINCT 
SELECT 
    a.id AS aid, a.name AS aname, 
    b.id AS bid, b.name AS bname 
FROM `BigqueryTest.colors` AS a 
LEFT JOIN `BigqueryTest.color2` AS b 
ON a.name = b.name