diff options
| -rw-r--r-- | railties/guides/source/active_record_querying.textile | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/railties/guides/source/active_record_querying.textile b/railties/guides/source/active_record_querying.textile index e0fab46db9..009d541106 100644 --- a/railties/guides/source/active_record_querying.textile +++ b/railties/guides/source/active_record_querying.textile @@ -759,7 +759,9 @@ This would generate a query which contains a +LEFT OUTER JOIN+ whereas the +join SELECT "posts"."id" AS t0_r0, ... "comments"."updated_at" AS t1_r5 FROM "posts" LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts"."id" WHERE (comments.visible) </ruby> -If in this case there were no comments for any posts, all the posts would still be loaded. By using +joins+ (an INNER JOIN), the join conditions *must* match, otherwise no records will be returned. +If there was no +where+ condition, this would generate the normal set of two queries. + +If, in the case of this +includes+ query, there were no comments for any posts, all the posts would still be loaded. By using +joins+ (an INNER JOIN), the join conditions *must* match, otherwise no records will be returned. h3. Scopes |