実例で学ぶ、PostgreSQLだとJOINが必要ないケース - Qiitatest=# SELECT unnest(tags) FROM articles WHERE id = 1; unnest -------- 0 1 (2 rows) test=# EXPLAIN SELECT unnest(tags) FROM articles WHERE id = 1; QUERY PLAN --------------------------------------------------------------------------------- Index Scan using articles_pkey on articles (cost=0.42..8.93 rows=100 width=32) Index Cond: (id = 1) (2 rows) test=# SELECT * FROM articles where tags @> ARRAY[1
