{"id":6444,"date":"2026-06-14T12:06:13","date_gmt":"2026-06-14T03:06:13","guid":{"rendered":"https:\/\/route-zero.com\/recruit\/?post_type=route&#038;p=6444"},"modified":"2026-10-14T12:06:21","modified_gmt":"2026-10-14T03:06:21","slug":"sql-nullif-division-by-zero","status":"publish","type":"route","link":"https:\/\/route-zero.com\/recruit\/route\/6444\/","title":{"rendered":"SQL\u306eNULLIF\u3067\u30bc\u30ed\u9664\u7b97\u3092\u9632\u3050\u65b9\u6cd5"},"content":{"rendered":"<p>SQL\u3067\u5272\u5408\u3092\u8a08\u7b97\u3059\u308b\u3068\u304d\u3001\u5206\u6bcd\u304c0\u306b\u306a\u3063\u3066\u30bc\u30ed\u9664\u7b97\u30a8\u30e9\u30fc\u306b\u306a\u308b\u306a\u3089\u3001\u5206\u6bcd\u3092NULLIF(\u5206\u6bcd, 0)\u306b\u7f6e\u304d\u63db\u3048\u308b\u306e\u304c\u7c21\u6f54\u306a\u5bfe\u51e6\u3067\u3059\u3002NULLIF\u306f2\u3064\u306e\u5024\u304c\u7b49\u3057\u3044\u3068\u304dNULL\u3092\u8fd4\u3059\u305f\u3081\u3001\u5206\u6bcd0\u3092NULL\u3078\u5909\u63db\u3067\u304d\u307e\u3059\u3002SQL Server\u3084PostgreSQL\u3067\u306f\u3001\u3053\u306e\u5f62\u3067\u30bc\u30ed\u9664\u7b97\u3092\u907f\u3051\u3089\u308c\u307e\u3059\u3002\u7d50\u679c\u306eNULL\u30920\u3078\u5909\u3048\u305f\u3044\u5834\u5408\u306fCOALESCE\u3092\u8ffd\u52a0\u3067\u304d\u307e\u3059\u304c\u3001\u300e\u8a08\u7b97\u4e0d\u80fd\u300f\u3092\u300e0%\u300f\u3078\u7f6e\u304d\u63db\u3048\u3066\u3088\u3044\u304b\u306f\u696d\u52d9\u4e0a\u306e\u610f\u5473\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<h2>\u307e\u305a\u30bc\u30ed\u9664\u7b97\u3092NULLIF\u3067\u76f4\u3059<\/h2>\n<p>\u305f\u3068\u3048\u3070\u6210\u529f\u4ef6\u6570\u3092\u7dcf\u4ef6\u6570\u3067\u5272\u308b\u5272\u5408\u8a08\u7b97\u3067\u3001\u7dcf\u4ef6\u6570\u304c0\u306b\u306a\u308b\u30b1\u30fc\u30b9\u3092\u8003\u3048\u307e\u3059\u3002\u5206\u6bcd\u3092\u305d\u306e\u307e\u307e\u4f7f\u3046\u306e\u3067\u306f\u306a\u304f\u3001NULLIF\u30670\u3060\u3051\u3092NULL\u3078\u5909\u63db\u3057\u307e\u3059\u3002<\/p>\n<pre><code>SELECT\r\n  100.0 * success_count \/ NULLIF(total_count, 0) AS success_rate\r\nFROM daily_stats;<\/code><\/pre>\n<p>total_count\u304c0\u306a\u3089NULLIF(total_count, 0)\u306fNULL\u306b\u306a\u308a\u307e\u3059\u3002\u5206\u6bcd\u304c0\u4ee5\u5916\u306a\u3089\u5143\u306etotal_count\u304c\u8fd4\u308b\u305f\u3081\u3001\u901a\u5e38\u306e\u884c\u306f\u305d\u306e\u307e\u307e\u8a08\u7b97\u3067\u304d\u307e\u3059\u3002<\/p>\n<hr>\n<h2>NULLIF\u306f\u4f55\u3092\u3057\u3066\u3044\u308b\u306e\u304b<\/h2>\n<p>NULLIF(a, b)\u306f\u3001a\u3068b\u304c\u7b49\u3057\u3044\u3068\u304dNULL\u3092\u8fd4\u3057\u3001\u7b49\u3057\u304f\u306a\u3051\u308c\u3070a\u3092\u8fd4\u3059\u5f0f\u3067\u3059\u3002\u30bc\u30ed\u9664\u7b97\u5bfe\u7b56\u3067\u306f\u300e\u5206\u6bcd\u304c0\u306a\u3089NULL\u306b\u3059\u308b\u300f\u3068\u3044\u3046\u5c0f\u3055\u306a\u6761\u4ef6\u5206\u5c90\u3068\u3057\u3066\u4f7f\u3044\u307e\u3059\u3002<\/p>\n<table>\n<thead>\n<tr>\n<th>total_count<\/th>\n<th>NULLIF(total_count, 0)<\/th>\n<th>\u7d50\u679c<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>10<\/td>\n<td>10<\/td>\n<td>\u901a\u5e38\u8a08\u7b97<\/td>\n<\/tr>\n<tr>\n<td>1<\/td>\n<td>1<\/td>\n<td>\u901a\u5e38\u8a08\u7b97<\/td>\n<\/tr>\n<tr>\n<td>0<\/td>\n<td>NULL<\/td>\n<td>\u8a08\u7b97\u7d50\u679c\u306fNULL<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<blockquote>\n<p><strong>\u7528\u8a9e\u89e3\u8aac\uff1aNULLIF<\/strong><br \/>2\u3064\u306e\u5f0f\u304c\u7b49\u3057\u3044\u3068\u304dNULL\u3092\u8fd4\u3057\u3001\u7570\u306a\u308b\u3068\u304d\u306f\u7b2c1\u5f15\u6570\u3092\u8fd4\u3059SQL\u306e\u6761\u4ef6\u5f0f\u3067\u3059\u3002<\/p>\n<\/blockquote>\n<hr>\n<h2>COALESCE\u30670\u3092\u8fd4\u3059\u3068\u304d\u306e\u6ce8\u610f<\/h2>\n<p>\u753b\u9762\u3084\u96c6\u8a08\u4ed5\u69d8\u3067NULL\u3067\u306f\u306a\u304f0\u3092\u8fd4\u3059\u5fc5\u8981\u304c\u3042\u308b\u5834\u5408\u306f\u3001\u8a08\u7b97\u7d50\u679c\u3092COALESCE\u3067\u5305\u3081\u307e\u3059\u3002<\/p>\n<pre><code>SELECT\r\n  COALESCE(100.0 * success_count \/ NULLIF(total_count, 0), 0) AS success_rate\r\nFROM daily_stats;<\/code><\/pre>\n<p>\u305f\u3060\u3057\u7dcf\u4ef6\u65700\u306e\u72b6\u614b\u306f\u3001\u672c\u6765\u306f\u300e\u5272\u5408\u3092\u8a08\u7b97\u3067\u304d\u306a\u3044\u300f\u72b6\u614b\u3067\u3059\u3002\u305d\u308c\u30920%\u3068\u8868\u793a\u3059\u308b\u3068\u610f\u5473\u304c\u5909\u308f\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002NULL\u306e\u307e\u307e\u8fd4\u3059\u304b0\u3078\u5909\u63db\u3059\u308b\u304b\u306f\u3001\u8868\u793a\u4ed5\u69d8\u3084\u96c6\u8a08\u30eb\u30fc\u30eb\u306b\u5408\u308f\u305b\u3066\u6c7a\u3081\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<blockquote>\n<p><strong>\u7528\u8a9e\u89e3\u8aac\uff1aCOALESCE<\/strong><br \/>\u5de6\u304b\u3089\u9806\u306b\u8a55\u4fa1\u3057\u3001\u6700\u521d\u306bNULL\u3067\u306f\u306a\u3044\u5024\u3092\u8fd4\u3059SQL\u306e\u6761\u4ef6\u5f0f\u3067\u3059\u3002NULL\u6642\u306e\u4ee3\u66ff\u5024\u3092\u6307\u5b9a\u3059\u308b\u3068\u304d\u306b\u4f7f\u3044\u307e\u3059\u3002<\/p>\n<\/blockquote>\n<hr>\n<h2>CASE\u5f0f\u3067\u66f8\u304f\u65b9\u6cd5\u3068\u306e\u9055\u3044<\/h2>\n<pre><code>SELECT\r\n  CASE\r\n    WHEN total_count = 0 THEN NULL\r\n    ELSE 100.0 * success_count \/ total_count\r\n  END AS success_rate\r\nFROM daily_stats;<\/code><\/pre>\n<p>\u5206\u6bcd0\u3060\u3051\u3092NULL\u306b\u3059\u308b\u306a\u3089NULLIF\u306e\u307b\u3046\u304c\u77ed\u304f\u66f8\u3051\u307e\u3059\u3002\u4e00\u65b9\u30010\u306e\u3068\u304d\u306b\u7279\u5225\u306a\u5024\u3092\u8fd4\u3059\u3001\u8907\u6570\u6761\u4ef6\u3067\u51e6\u7406\u3092\u5909\u3048\u308b\u306a\u3069\u6761\u4ef6\u5206\u5c90\u304c\u5897\u3048\u308b\u5834\u5408\u306fCASE\u5f0f\u306e\u307b\u3046\u304c\u610f\u56f3\u3092\u8aad\u307f\u53d6\u308a\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<h2>\u5b9f\u52d9\u3067\u78ba\u8a8d\u3057\u305f\u30444\u3064\u306e\u30dd\u30a4\u30f3\u30c8<\/h2>\n<ul>\n<li>\u3069\u306e\u5217\u304c\u5206\u6bcd\u306b\u306a\u308b\u304b\u3092\u5148\u306b\u78ba\u8a8d\u3059\u308b<\/li>\n<li>\u5206\u6bcd0\u3092NULL\u3068\u3057\u3066\u6271\u3046\u304b\u30010\u3068\u3057\u3066\u8868\u793a\u3059\u308b\u304b\u4ed5\u69d8\u3092\u6c7a\u3081\u308b<\/li>\n<li>\u6574\u6570\u540c\u58eb\u306e\u9664\u7b97\u3084\u578b\u5909\u63db\u306f\u5229\u7528DB\u306e\u6570\u5024\u578b\u30eb\u30fc\u30eb\u3092\u78ba\u8a8d\u3059\u308b<\/li>\n<li>\u8907\u96d1\u306a\u6761\u4ef6\u306a\u3089NULLIF\u3060\u3051\u3067\u8a70\u3081\u8fbc\u307e\u305aCASE\u5f0f\u3078\u5207\u308a\u66ff\u3048\u308b<\/li>\n<\/ul>\n<p>NULLIF\u306f\u30bc\u30ed\u9664\u7b97\u3092\u96a0\u3059\u305f\u3081\u306e\u4e07\u80fd\u306a\u51e6\u7406\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u30020\u4ef6\u304c\u767a\u751f\u3059\u308b\u7406\u7531\u305d\u306e\u3082\u306e\u304c\u30c7\u30fc\u30bf\u4e0d\u5099\u306a\u3089\u3001\u30af\u30a8\u30ea\u3060\u3051\u3067\u306a\u304f\u96c6\u8a08\u6761\u4ef6\u3084\u5143\u30c7\u30fc\u30bf\u3082\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<h2>\u95a2\u9023\u3059\u308bSQL\u306eNULL\u30fb\u6761\u4ef6\u5206\u5c90<\/h2>\n<p>NULL\u305d\u306e\u3082\u306e\u306e\u6271\u3044\u3092\u6574\u7406\u3057\u305f\u3044\u5834\u5408\u306fNULL\u89e3\u8aac\u3001\u8907\u6570\u6761\u4ef6\u3067\u7d50\u679c\u3092\u5207\u308a\u66ff\u3048\u305f\u3044\u5834\u5408\u306fCASE\u5f0f\u306e\u8a18\u4e8b\u304c\u53c2\u8003\u306b\u306a\u308a\u307e\u3059\u3002SQL\u5168\u4f53\u306e\u69cb\u6587\u3092\u78ba\u8a8d\u3057\u305f\u3044\u5834\u5408\u306f\u30b3\u30de\u30f3\u30c9\u4e00\u89a7\u3082\u4f7f\u3048\u307e\u3059\u3002<\/p>\n<p>\uff08SQL\u306eNULL\u3068COALESCE\u3092\u6574\u7406\u3059\u308b\u306b\u3064\u3044\u3066\u306f\u300e<a href=\"https:\/\/route-zero.com\/recruit\/route\/1764\/\">SQL NULL\u5b8c\u5168\u653b\u7565\uff5cIS NULL\u30fbCOALESCE\u306e\u4f7f\u3044\u5206\u3051\u3068DB\u5225\u30d0\u30b0\u9632\u6b62\u88535\u9078<\/a>\u300f\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\uff09<\/p>\n<p>\uff08CASE\u5f0f\u3067\u6761\u4ef6\u5206\u5c90\u3059\u308b\u306b\u3064\u3044\u3066\u306f\u300e<a href=\"https:\/\/route-zero.com\/recruit\/route\/1323\/\">SQL CASE\u5f0f\u306e\u4f7f\u3044\u65b9\uff5cSELECT\u30fbWHERE\u30fbUPDATE\u3067\u6761\u4ef6\u5206\u5c90\u3059\u308b\u66f8\u304d\u65b9\u3068\u3064\u307e\u305a\u304d\u89e3\u6d88\u5b9f\u4f8b<\/a>\u300f\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\uff09<\/p>\n<p>\uff08SQL\u30b3\u30de\u30f3\u30c9\u3092\u307e\u3068\u3081\u3066\u78ba\u8a8d\u3059\u308b\u306b\u3064\u3044\u3066\u306f\u300e<a href=\"https:\/\/route-zero.com\/recruit\/route\/1842\/\">SQL\u30b3\u30de\u30f3\u30c9\u4e00\u89a721\u9078\uff5c\u30b7\u30fc\u30f3\u5225\u3067\u8ff7\u308f\u306a\u3044\u4f7f\u3044\u65b9\uff0b\u30c1\u30fc\u30c8\u30b7\u30fc\u30c8<\/a>\u300f\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\uff09<\/p>\n<h2>\u3088\u304f\u3042\u308b\u7591\u554f<\/h2>\n<h3>NULLIF(0, 0)\u306f\u4f55\u3092\u8fd4\u3059\uff1f<\/h3>\n<p>NULL\u3092\u8fd4\u3057\u307e\u3059\u3002\u30bc\u30ed\u9664\u7b97\u5bfe\u7b56\u3067\u306f\u3001\u3053\u306e\u6027\u8cea\u3092\u4f7f\u3063\u3066\u5206\u6bcd\u306e0\u3060\u3051\u3092NULL\u3078\u5909\u63db\u3057\u307e\u3059\u3002<\/p>\n<h3>COALESCE\u3067\u5fc5\u305a0\u306b\u3057\u305f\u307b\u3046\u304c\u3088\u3044\uff1f<\/h3>\n<p>\u5fc5\u305a\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u5206\u6bcd0\u304c\u300e\u5272\u5408\u3092\u8a08\u7b97\u3067\u304d\u306a\u3044\u300f\u610f\u5473\u306a\u3089\u3001NULL\u30920%\u3078\u5909\u3048\u308b\u3068\u610f\u5473\u304c\u5909\u308f\u308b\u305f\u3081\u4ed5\u69d8\u306b\u5408\u308f\u305b\u3066\u5224\u65ad\u3057\u307e\u3059\u3002<\/p>\n<h3>NULLIF\u3068CASE\u306f\u3069\u3061\u3089\u304c\u901f\u3044\uff1f<\/h3>\n<p>\u3053\u306e\u8a18\u4e8b\u3067\u306f\u6027\u80fd\u306e\u512a\u52a3\u3092\u4e00\u822c\u5316\u3057\u307e\u305b\u3093\u3002\u5358\u7d14\u306a\u5206\u6bcd0\u306e\u7f6e\u63db\u306a\u3089NULLIF\u306f\u7c21\u6f54\u3067\u3001\u8907\u96d1\u306a\u6761\u4ef6\u5206\u5c90\u306a\u3089CASE\u306e\u307b\u3046\u304c\u610f\u56f3\u3092\u8868\u3057\u3084\u3059\u3044\u3068\u3044\u3046\u53ef\u8aad\u6027\u306e\u89b3\u70b9\u3067\u9078\u3073\u307e\u3059\u3002<\/p>\n<h2>\u307e\u3068\u3081<\/h2>\n<p>\u30bc\u30ed\u9664\u7b97\u3092\u907f\u3051\u308b\u6700\u5c0f\u306e\u4fee\u6b63\u306f\u3001\u5206\u6bcd\u3092NULLIF(\u5206\u6bcd, 0)\u306b\u3059\u308b\u3053\u3068\u3067\u3059\u3002\u7d50\u679c\u306eNULL\u30920\u3078\u5909\u3048\u308b\u306a\u3089COALESCE\u3092\u7d44\u307f\u5408\u308f\u305b\u3089\u308c\u307e\u3059\u304c\u3001\u305d\u306e\u5909\u63db\u304c\u696d\u52d9\u4e0a\u6b63\u3057\u3044\u304b\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u6761\u4ef6\u304c\u5897\u3048\u308b\u306a\u3089CASE\u5f0f\u3078\u5207\u308a\u66ff\u3048\u308b\u3068\u3001\u610f\u56f3\u3092\u4fdd\u3061\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u307e\u305a\u30bc\u30ed\u9664\u7b97\u304c\u8d77\u304d\u308b\u30af\u30a8\u30ea\u306e\u5206\u6bcd\u3092\u78ba\u8a8d\u3057\u3001NULLIF\u30670\u3060\u3051\u3092NULL\u306b\u3057\u305f\u7d50\u679c\u3092\u30c6\u30b9\u30c8\u3057\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"featured_media":6450,"template":"","meta":{"ssp_meta_title":"SQL\u306eNULLIF\u3068\u306f\uff1f\u30bc\u30ed\u9664\u7b97\u3092\u9632\u3050\u4f7f\u3044\u65b9\u3068COALESCE\u306e\u7d44\u307f\u5408\u308f\u305b","ssp_meta_description":"SQL\u306e\u5272\u5408\u8a08\u7b97\u3067\u30bc\u30ed\u9664\u7b97\u3092\u9632\u3050NULLIF\u306e\u4f7f\u3044\u65b9\u3092\u89e3\u8aac\u3002\u5206\u6bcd\u304c0\u306e\u3068\u304dNULL\u3078\u5909\u63db\u3059\u308b\u4ed5\u7d44\u307f\u3001COALESCE\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\u3001CASE\u5f0f\u3068\u306e\u9055\u3044\u3092SQL Server\u30fbPostgreSQL\u306e\u4f8b\u3067\u6574\u7406\u3057\u307e\u3059\u3002","ssp_meta_keyword":"SQL NULLIF \u30bc\u30ed\u9664\u7b97,SQL NULLIF,SQL division by zero,SQL COALESCE NULLIF,SQL CASE \u30bc\u30ed\u9664\u7b97,SQL \u5272\u5408\u8a08\u7b97","ssp_meta_canonical":""},"route_category":[9],"_links":{"self":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route\/6444"}],"collection":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route"}],"about":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/types\/route"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/media\/6450"}],"wp:attachment":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/media?parent=6444"}],"wp:term":[{"taxonomy":"route_category","embeddable":true,"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route_category?post=6444"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}