Ruby on rails 使用Arel表示CTE
我有一段ActiveRecord:Ruby on rails 使用Arel表示CTE,ruby-on-rails,postgresql,activerecord,common-table-expression,arel,Ruby On Rails,Postgresql,Activerecord,Common Table Expression,Arel,我有一段ActiveRecord: scope = Listing.where(Listing.arel_table[:price].gt(6_000_000)) 生成的sql: SELECT listings.* FROM listings where listings.price > 6000000 我想添加一个CTE,它将产生以下sql: WITH lookup AS ( SELECT the_geom FROM lookup WHERE slug = 'foo-bar'
scope = Listing.where(Listing.arel_table[:price].gt(6_000_000))
生成的sql:
SELECT listings.* FROM listings where listings.price > 6000000
我想添加一个CTE,它将产生以下sql:
WITH lookup AS (
SELECT the_geom FROM lookup WHERE slug = 'foo-bar'
)
SELECT * from listings, lookup
WHERE listings.price > 6000000
AND ST_within(listings.the_geom, lookup.the_geom)
我想用Arel和ActiveRecord来表达这个包含CTE的sql
我还想使用scope变量作为起点。您可以创建如下CTE:
lookup = Arel::Table.new(:lookup) # Lookup.arel_table
cte = Arel::Nodes::As.new(lookup,
lookup.where(lookup[:slug].eq('foo-bar')).project('the_geom'))
然后将其用于您的范围,如:
scope.with(cte)
您可以在中看到一个示例,在最底部尝试此操作,会导致中缺少一个
。也就是说,只需SELECT*FROM listings WHERE
notSELECT*FROM listings,lookup WHERE
通过添加joins
:scope.joins('CROSS-JOIN lookup')。使用(cte)