{"id":6143,"date":"2025-10-04T15:59:07","date_gmt":"2025-10-04T06:59:07","guid":{"rendered":"https:\/\/sky-peace.net\/?p=6143"},"modified":"2025-10-04T15:59:07","modified_gmt":"2025-10-04T06:59:07","slug":"sql-if","status":"publish","type":"post","link":"https:\/\/sky-peace.net\/certified\/sql-if\/","title":{"rendered":"SQL\u306e\u57fa\u672c\u7406\u89e3\uff1aIF\u6587\u306e\u5165\u308c\u5b50\u3068\u51e6\u7406\u306e\u6d41\u308c\u3001\u96c6\u8a08\u95a2\u6570\u3068\u62ec\u5f27\u306e\u95a2\u4fc2"},"content":{"rendered":"
\n

SQL\u3092\u5b66\u3076\u3068\u304d\u306b\u591a\u304f\u306e\u4eba\u304c\u3064\u307e\u305a\u304f\u30dd\u30a4\u30f3\u30c8\u304c\u300cIF\u6587\u306e\u5165\u308c\u5b50\u3068\u51e6\u7406\u306e\u6d41\u308c\u300d\u3001\u305d\u3057\u3066\u300c\u96c6\u8a08\u95a2\u6570\u306b\u304a\u3051\u308b\u62ec\u5f27()\u306e\u6271\u3044\u300d\u3067\u3059\u3002\u672c\u8a18\u4e8b\u3067\u306f\u3001\u3053\u306e2\u3064\u3092\u6574\u7406\u3057\u306a\u304c\u3089\u3001\u521d\u5b66\u8005\u3067\u3082\u30a4\u30e1\u30fc\u30b8\u3057\u3084\u3059\u3044\u3088\u3046\u306b\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n

IF\u6587\u306b\u304a\u3051\u308b\u5165\u308c\u5b50\u3068\u5206\u5c90\u306e\u4ed5\u7d44\u307f<\/h2>\n

\u5165\u308c\u5b50\u69cb\u9020\u306e\u8003\u3048\u65b9<\/h3>\n

SQL\u306e\u30b9\u30c8\u30a2\u30c9\u30d7\u30ed\u30b7\u30fc\u30b8\u30e3\u3084\u5236\u5fa1\u69cb\u6587\u3067\u306f\u3001IF\u6587\u3092\u5165\u308c\u5b50\u306b\u3059\u308b\u3053\u3068\u3067\u6761\u4ef6\u306b\u968e\u5c64\u3092\u6301\u305f\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u5916\u5074\u306eIF\u304c\u771f\u3067\u3042\u308c\u3070\u3001\u305d\u306e\u5185\u90e8\u3067\u3055\u3089\u306b\u5225\u306e\u6761\u4ef6\u3092\u8a55\u4fa1\u3067\u304d\u307e\u3059\u3002\u9006\u306b\u3001\u5916\u5074\u304c\u507d\u306a\u3089\u5185\u90e8\u306e\u6761\u4ef6\u5224\u5b9a\u306f\u4e00\u5207\u884c\u308f\u308c\u307e\u305b\u3093\u3002<\/p>\n

\n  IF update_flag = 0 THEN\n      IF g = 1 THEN\n          UPDATE \u4f1a\u54e1 SET ...\n      END IF;\n  END IF;\n  <\/code><\/pre>\n
\u89aaIF\u304cfalse\u306e\u3068\u304d\u5b50IF\u306f\u3069\u3046\u306a\u308b\uff1f<\/h3>\n
\u89aaIF\u304cfalse\u306a\u3089\u3001\u305d\u306e\u30d6\u30ed\u30c3\u30af\u306e\u4e2d\u8eab\u306f\u30b9\u30ad\u30c3\u30d7\u3055\u308c\u307e\u3059\u3002\u3064\u307e\u308a\u3001\u5b50IF\u306f\u5b9f\u884c\u3055\u308c\u305a\u3001\u5224\u5b9a\u81ea\u4f53\u3082\u884c\u308f\u308c\u307e\u305b\u3093\u3002\u30a4\u30e1\u30fc\u30b8\u3068\u3057\u3066\u306f\u300c\u89aaIF\u304c\u5165\u5834\u30b2\u30fc\u30c8\u3001\u5b50IF\u304c\u30b2\u30fc\u30c8\u306e\u4e2d\u306e\u6249\u300d\u306e\u3088\u3046\u306a\u95a2\u4fc2\u3067\u3059\u3002<\/p>\n
\u4e26\u5217\u306b\u66f8\u3044\u305f\u5834\u5408\u3068\u306e\u9055\u3044<\/h3>\n
\u3082\u3057\u540c\u3058\u6761\u4ef6\u3092\u5165\u308c\u5b50\u3067\u306f\u306a\u304f\u4e26\u5217\u306b\u66f8\u3044\u305f\u5834\u5408\u3001\u89aaIF\u304cfalse\u3067\u3082\u5b50IF\u306f\u72ec\u7acb\u3057\u3066\u5224\u5b9a\u3055\u308c\u307e\u3059\u3002\u51e6\u7406\u30d5\u30ed\u30fc\u306b\u9055\u3044\u304c\u51fa\u308b\u305f\u3081\u3001\u696d\u52d9\u30ed\u30b8\u30c3\u30af\u306b\u5fdc\u3058\u3066\u300c\u5165\u308c\u5b50\u300d\u3068\u300c\u4e26\u5217\u300d\u3092\u4f7f\u3044\u5206\u3051\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n
SQL\u306b\u304a\u3051\u308b\u51e6\u7406\u306e\u9806\u756a\u306e\u91cd\u8981\u6027<\/h2>\n
\u4e0a\u304b\u3089\u9806\u756a\u306b\u5b9f\u884c\u3055\u308c\u308b\u30eb\u30fc\u30eb<\/h3>\n
\u624b\u7d9a\u304d\u578bSQL\u306f\u57fa\u672c\u7684\u306b\u4e0a\u304b\u3089\u4e0b\u3078\u51e6\u7406\u304c\u6d41\u308c\u307e\u3059\u3002\u5909\u6570\u306e\u4ee3\u5165\u3084UPDATE\u306e\u9806\u5e8f\u304c\u5909\u308f\u308b\u3060\u3051\u3067\u3001\u5f8c\u7d9a\u306e\u51e6\u7406\u7d50\u679c\u3082\u5909\u308f\u308b\u70b9\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n
\u30cd\u30b9\u30c8\u3068\u9806\u5e8f\u306e\u7d44\u307f\u5408\u308f\u305b\u306b\u3088\u308b\u9055\u3044<\/h3>\n
\u300c\u89aaIF\u304ctrue\u306e\u3068\u304d\u3060\u3051\u5b50IF\u304c\u5b9f\u884c\u3055\u308c\u308b\u300d\u69cb\u9020\u306b\u52a0\u3048\u3066\u3001\u300c\u51e6\u7406\u306f\u4e0a\u304b\u3089\u9806\u306b\u5b9f\u884c\u3055\u308c\u308b\u300d\u30eb\u30fc\u30eb\u304c\u7d44\u307f\u5408\u308f\u3055\u308b\u305f\u3081\u3001\u5b9f\u969b\u306e\u30d5\u30ed\u30fc\u8a2d\u8a08\u3067\u306f\u610f\u56f3\u901a\u308a\u306b\u66f8\u3051\u3066\u3044\u308b\u304b\u3092\u614e\u91cd\u306b\u78ba\u8a8d\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n
\u96c6\u8a08\u95a2\u6570\u3068\u62ec\u5f27()\u306e\u95a2\u4fc2<\/h2>\n
\u96c6\u8a08\u95a2\u6570\u306f\u5fc5\u305a()\u304c\u5fc5\u8981\u306a\u7406\u7531<\/h3>\n
SUM\u3084AVG\u306a\u3069\u306e\u96c6\u8a08\u95a2\u6570\u306f\u3001SQL\u306b\u304a\u3044\u3066\u300c\u95a2\u6570\u547c\u3073\u51fa\u3057\u300d\u306e\u5f62\u5f0f\u3092\u53d6\u308a\u307e\u3059\u3002\u305d\u306e\u305f\u3081\u3001\u5f15\u6570\u3092\u5fc5\u305a\u62ec\u5f27\u3067\u56f2\u3080\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u62ec\u5f27\u3092\u7701\u7565\u3059\u308b\u3068\u69cb\u6587\u30a8\u30e9\u30fc\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
COUNT(*)\u3084DISTINCT\u306e\u6b63\u3057\u3044\u4f7f\u3044\u65b9<\/h3>\n
    \n
  • \u6b63\u3057\u3044\u4f8b: COUNT(*)<\/code><\/li>\n
  • \u6b63\u3057\u3044\u4f8b: COUNT(DISTINCT department_id)<\/code><\/li>\n
  • \u8aa4\u308a: COUNT *<\/code> \/ COUNT DISTINCT department_id<\/code><\/li>\n<\/ul>\n
    \u3053\u306e\u3088\u3046\u306b\u3001COUNT\u3067\u3042\u3063\u3066\u3082\u62ec\u5f27\u306f\u5fc5\u9808\u3067\u3042\u308a\u3001DISTINCT\u3092\u4f7f\u3046\u5834\u5408\u3082\u5fc5\u305a\u62ec\u5f27\u306e\u4e2d\u306b\u542b\u3081\u307e\u3059\u3002<\/p>\n
    \u3088\u304f\u3042\u308b\u9593\u9055\u3044\u3068\u30a8\u30e9\u30fc\u4f8b<\/h3>\n\n\n\n\n\n\n\n\n
    \u95a2\u6570<\/th>\n\u6b63\u3057\u3044\u66f8\u304d\u65b9<\/th>\n\u8aa4\u308a\u4f8b<\/th>\n<\/tr>\n<\/thead>\n
    SUM<\/td>\nSUM(salary)<\/td>\nSUM salary<\/td>\n<\/tr>\n
    AVG<\/td>\nAVG(price)<\/td>\nAVG price<\/td>\n<\/tr>\n
    COUNT<\/td>\nCOUNT(*)<\/td>\nCOUNT *<\/td>\n<\/tr>\n
    COUNT DISTINCT<\/td>\nCOUNT(DISTINCT col)<\/td>\nCOUNT DISTINCT col<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    \u8aa4\u3063\u305f\u66f8\u304d\u65b9\u3092\u3059\u308b\u3068\u300csyntax error\u300d\u3084\u300cmissing parenthesis\u300d\u306a\u3069\u306e\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3057\u307e\u3059\u3002\u62ec\u5f27\u306f\u5fc5\u9808\u3060\u3068\u899a\u3048\u3066\u304a\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n
    \u307e\u3068\u3081<\/h2>\n
    SQL\u3092\u6b63\u3057\u304f\u6271\u3046\u305f\u3081\u306b\u306f\u3001IF\u6587\u306e\u5165\u308c\u5b50\u3068\u5206\u5c90\u306e\u6d41\u308c\u3092\u7406\u89e3\u3057\u3001\u307e\u305f\u96c6\u8a08\u95a2\u6570\u306f\u5fc5\u305a\u62ec\u5f27\u304c\u5fc5\u8981\u3060\u3068\u3044\u3046\u30eb\u30fc\u30eb\u3092\u5b88\u308b\u3053\u3068\u304c\u5927\u5207\u3067\u3059\u3002\u51e6\u7406\u306e\u6d41\u308c\u3092\u6b63\u78ba\u306b\u30a4\u30e1\u30fc\u30b8\u3057\u3001\u30a8\u30e9\u30fc\u3092\u672a\u7136\u306b\u9632\u304e\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/article>\n","protected":false},"excerpt":{"rendered":"
    SQL\u3092\u5b66\u3076\u3068\u304d\u306b\u591a\u304f\u306e\u4eba\u304c\u3064\u307e\u305a\u304f\u30dd\u30a4\u30f3\u30c8\u304c\u300cIF\u6587\u306e\u5165\u308c\u5b50\u3068\u51e6\u7406\u306e\u6d41\u308c\u300d\u3001\u305d\u3057\u3066\u300c\u96c6\u8a08\u95a2\u6570\u306b\u304a\u3051\u308b\u62ec\u5f27()\u306e\u6271\u3044\u300d\u3067\u3059\u3002\u672c\u8a18\u4e8b\u3067\u306f\u3001\u3053\u306e2\u3064\u3092\u6574\u7406\u3057\u306a\u304c\u3089\u3001\u521d\u5b66\u8005\u3067\u3082\u30a4\u30e1\u30fc\u30b8\u3057\u3084\u3059\u3044\u3088\u3046\u306b\u89e3\u8aac\u3057\u307e … <\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","columnck":"","stmeta_robots":"index, follow","st_titlewords":"","st_title_extra":"","st_keywords":"","st_description":"","st_display_ad_mark":"","st_display_ad_mark_hide":"","textcopyck":"","st_copyright":"","st_copyurl":"","eyecatch_set":"","st_youtube_url":"","st_youtube_eyecatch":"","headerwidget_set":"","updatewidget_set":"","kanrenwidget_set":"","ikkatuwidget_set":"","koukoku_set":"","auto_adsense_koukoku_set":"","st_redirect":"","st_redirect_url_as_canonical":"","st_redirect_pvm_do_not_track":"","post_data_updatewidget_set":"","st_post_header_under_bg":"","st_twitter_tag":"","affinger_note":"","rankdisplayck":"","st_head_code":"","st_footer_code":"","st_post_header_under_code":"","_st_toc_override":false,"_st_toc_settings":[]},"categories":[3],"tags":[6],"class_list":["post-6143","post","type-post","status-publish","format-standard","hentry","category-ipa","tag-6"],"_links":{"self":[{"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/posts\/6143","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/comments?post=6143"}],"version-history":[{"count":0,"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/posts\/6143\/revisions"}],"wp:attachment":[{"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/media?parent=6143"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/categories?post=6143"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sky-peace.net\/certified\/wp-json\/wp\/v2\/tags?post=6143"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}