多个子查询加入

Question

SELECt rb.resource_id, re.code,rb.TYPE, 
(
    SELECT i18n_resourcebase.NAME 
    FROM i18n_resourcebase 
    WHERE language_id=1 
    AND (i18n_resourcebase.resource_id = rb.resource_id)
) nl_name, 
( 
    SELECT i18n_resourcebase.NAME 
    FROM i18n_resourcebase 
    WHERE language_id=21 
    AND (i18n_resourcebase.resource_id = rb.resource_id)
) de_name, 
(
    SELECT i18n_resourcebase.NAME 
    FROM i18n_resourcebase 
    WHERE language_id=22 
    AND (i18n_resourcebase.resource_id = rb.resource_id)
) en_name

FROM resourcebase rb 
JOIN resort re ON (rb.resort_id=re.resort_id) 
AND re.code='RVRP' 
AND rb.TYPE='accommodationtype' 
AND rb.archived_from IS NULL 
AND re.archived_from IS NULL;

我想用连接替换子查询；我该怎么做？

Answer 1

SELECt rb.resource_id, MAX(re.code),MAX(rb.TYPE),
  MAX(CASE WHEN irb.language_id=1 THEN irb.NAME END) as nl_name, 
  MAX(CASE WHEN irb.language_id=21 THEN irb.NAME END) as de_name, 
  MAX(CASE WHEN irb.language_id=22 THEN irb.NAME END) as en_name
FROM resourcebase rb 
JOIN resort re ON (rb.resort_id=re.resort_id) 
LEFT JOIN i18n_resourcebase irb on (irb.resource_id = rb.resource_id)
AND re.code='RVRP' 
AND rb.TYPE='accommodationtype' 
AND rb.archived_from IS NULL 
AND re.archived_from IS NULL

GROUP BY rb.resource_id;

多个子查询加入

Multiple SUbqueries into Join

sql

oracle

join

subquery