Rails ã«ãŠã‘る内部çµåˆã€å¤–部çµåˆã¾ã¨ã‚ - Qiita0. ã¯ã˜ã‚ã« Qiitaã¯ã˜ã‚ã€ã•ã¾ã–ã¾ãªã¨ã“ã‚ã§Railsã®ActiveRecordã®å†…部çµåˆã‚„外部çµåˆã«é–¢ã™ã‚‹è¨˜äº‹ãŒã‚ã‚Šã¾ã™ãŒã€ãれらãŒã¾ã¨ã¾ã£ã¦å˜åœ¨ã—ã¦ã„ã‚‹ã¨è‰¯ã„リファレンスã¨ãªã‚‹ã®ã§ã¯ãªã„ã‹ã¨æ€ã„本記事を作æˆã—ã¾ã—ãŸã€‚ ã¾ãŸã€Rails5ã§å‹•ä½œç¢ºèªã—ã¦ãŠããªãŒã‚‰ã€Rails5ã‹ã‚‰è¿½åŠ ã•ã‚ŒãŸleft_outer_joinsãªã©ã¯è¼‰ã›ã¦ã¾ã›ã‚“。今後ã€è¼‰ã›ã¦ã„ããŸã„ã¨æ€ã„ã¾ã™ã€‚ group byやサブクエリ（副å•ã„åˆã‚ã›ï¼‰ã«é–¢ã—ã¦ã¯ä¸‹è¨˜ã‚‚ã”å‚ç…§ãã ã•ã„。 ActiveRecordã«ãŠã‘ã‚‹GROUP BYã®ä½¿ã„æ–¹ ActiveRecordã§ã‚µãƒ–クエリ（副å•ã„åˆã‚ã›ï¼‰ã¨å†…部çµåˆ 0-1. Rubyã¨Railsã¨PostgreSQLã®ãƒãƒ¼ã‚¸ãƒ§ãƒ³ $ ruby -v ruby 2.2.4p230 (2015-12-16 revision 53155) [x86_64-darwin15] $ r
{{#tags}}- {{label}}
{{/tags}}