Django equivalent for count and group by
I have a model that looks like this: class Category(models.Model): name = models.CharField(max_length=60) class Item(models.Model): name = models.CharField(max_length=60) category = models.ForeignKey(Category) I want select count (just the count) of items for each category, so in SQL it would be as simple as this: select category_id, count(id) from item group by category_id Is there an equivalent
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よã忘れã¦Google先生ã«å°‹ãる羽目ã«ãªã‚‹ã®ã§ãƒ¡ãƒ¢æ›¸ã。 Djangoã®ãƒ‡ãƒ¼ã‚¿ãƒ™ãƒ¼ã‚¹ãƒ©ãƒƒãƒ‘ã§ã‚ã‚‹filterを使ã†æ™‚ã€SQLã§è¨€ã†ã€Œwhere a like ...ã€ã‚„「where a > 0ã€ã¨ã‹ã‚’ã€filterã§ã¯ã©ã†æ›¸ãã®ã‹å¿˜ã‚Œã¾ã™ã€‚例ãˆã°å®Œå…¨ä¸€è‡´ã ã¨ã€SQLã®å ´åˆã¯ã€Œwhere a == ...ã€ã§ã™ãŒfilterã®å ´åˆã¯ã€Œfilter(a__exact=...)ã€ãªã„ã—ã¯ã€Œfilter(a=...)ã€ã¨ãªã‚Šã¾ã™ã€‚ ã¡ãªã¿ã«ã€DBソフトã«ã‚ˆã£ã¦ã¯ã€å¤§æ–‡å—å°æ–‡å—区別ãŒç„¡ã‹ã£ãŸã‚Šã—ã¾ã™ã€‚ 挙動 SQL上ã§ã®æ¼”ç®—å Django Filter 例 完全一致 = a*1 a = ... 完全一致 = exact a__exact=... 大文å—å°æ–‡å—区別無ã—ã®ä¸€è‡´ iLIKE '...' iexact a__iexact=... 大文å—å°æ–‡å—区別有りã®éƒ¨åˆ†ä¸€è‡´ like '%...%'
A step-by-step SQLAlchemy tutorial
About This Tutorial This tutorial is for SQLAlchemy version 0.2. You may notice that some sections are marked "New in 0.2". If this is the first time you're reading this tutorial, you can safely skip those sections. On the other hand, if you read the previous version of this tutorial and are now trying to learn SQLAlchemy 0.2, then just search for the text "New in 0.2" and you'll have a lot less r
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