{"id":6422,"date":"2026-04-08T14:37:41","date_gmt":"2026-04-08T05:37:41","guid":{"rendered":"https:\/\/route-zero.com\/recruit\/?post_type=route&#038;p=6422"},"modified":"2026-10-08T14:38:02","modified_gmt":"2026-10-08T05:38:02","slug":"sql-count-star-vs-column-null","status":"publish","type":"route","link":"https:\/\/route-zero.com\/recruit\/route\/6422\/","title":{"rendered":"SQL\u306eCOUNT(*)\u3068COUNT(\u5217)\u306e\u9055\u3044\uff5cNULL\u3067\u4ef6\u6570\u304c\u5909\u308f\u308b\u7406\u7531"},"content":{"rendered":"<p>`COUNT(*)`\u3068`COUNT(\u5217)`\u306e\u9055\u3044\u306f\u3001\u4f55\u3092\u6570\u3048\u308b\u304b\u3067\u3059\u3002`COUNT(*)`\u306f\u7d50\u679c\u30bb\u30c3\u30c8\u306e\u884c\u6570\u3092\u6570\u3048\u3001`COUNT(\u5217)`\u306f\u305d\u306e\u5217\u306e\u5024\u304c`NULL`\u3067\u306f\u306a\u3044\u884c\u3060\u3051\u3092\u6570\u3048\u307e\u3059\u3002\u4ef6\u6570\u304c\u5408\u308f\u306a\u3044\u3068\u304d\u306f\u3001\u307e\u305a\u5bfe\u8c61\u5217\u306b`NULL`\u304c\u306a\u3044\u304b\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u884c\u6570\u3092\u77e5\u308a\u305f\u3044\u306a\u3089`COUNT(*)`\u3001\u5024\u304c\u5165\u3063\u3066\u3044\u308b\u4ef6\u6570\u3092\u77e5\u308a\u305f\u3044\u306a\u3089`COUNT(\u5217)`\u3068\u8003\u3048\u308b\u3068\u5224\u65ad\u3057\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<h2>\u307e\u305a\u7d50\u8ad6\uff1aCOUNT(*)\u306f\u884c\u6570\u3001COUNT(\u5217)\u306fNULL\u3067\u306a\u3044\u5024\u3092\u6570\u3048\u308b<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u66f8\u304d\u65b9<\/th>\n<th>\u6570\u3048\u308b\u5bfe\u8c61<\/th>\n<th>NULL\u306e\u6271\u3044<\/th>\n<th>\u5411\u3044\u3066\u3044\u308b\u7528\u9014<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>COUNT(*)<\/td>\n<td>\u7d50\u679c\u30bb\u30c3\u30c8\u306e\u5168\u884c<\/td>\n<td>\u5217\u304cNULL\u3067\u3082\u884c\u3068\u3057\u3066\u6570\u3048\u308b<\/td>\n<td>\u7dcf\u4ef6\u6570\u30fb\u7dcf\u30ec\u30b3\u30fc\u30c9\u6570<\/td>\n<\/tr>\n<tr>\n<td>COUNT(\u5217)<\/td>\n<td>\u6307\u5b9a\u5217\u304cNULL\u3067\u306f\u306a\u3044\u884c<\/td>\n<td>NULL\u3092\u6570\u3048\u306a\u3044<\/td>\n<td>\u5165\u529b\u6e08\u307f\u4ef6\u6570\u30fb\u5024\u3042\u308a\u4ef6\u6570<\/td>\n<\/tr>\n<tr>\n<td>COUNT(DISTINCT \u5217)<\/td>\n<td>\u6307\u5b9a\u5217\u306e\u91cd\u8907\u3057\u306a\u3044\u975eNULL\u5024<\/td>\n<td>NULL\u3092\u6570\u3048\u305a\u91cd\u8907\u3082\u307e\u3068\u3081\u308b<\/td>\n<td>\u30e6\u30cb\u30fc\u30af\u30e6\u30fc\u30b6\u30fc\u6570\u30fb\u7a2e\u985e\u6570<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>PostgreSQL 18\u306e\u516c\u5f0f\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u3067\u306f\u3001`count(*)`\u306f\u5165\u529b\u884c\u6570\u3001`count(expression)`\u306f\u5f0f\u306e\u5024\u304cNULL\u3067\u306f\u306a\u3044\u5165\u529b\u884c\u6570\u3068\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002SQL Server\u306eCOUNT\u3082\u540c\u3058\u533a\u5225\u3092\u6301\u3061\u307e\u3059\u3002\u3064\u307e\u308a\u3001COUNT\u306e\u7d50\u679c\u5dee\u306f\u300e\u884c\u3092\u6570\u3048\u305f\u3044\u306e\u304b\u300f\u300e\u7279\u5b9a\u306e\u5024\u304c\u5b58\u5728\u3059\u308b\u884c\u3092\u6570\u3048\u305f\u3044\u306e\u304b\u300f\u3067\u6c7a\u307e\u308a\u307e\u3059\u3002<\/p>\n<hr>\n<h2>5\u884c\u306e\u30c7\u30fc\u30bf\u3067COUNT\u306e\u9055\u3044\u3092\u78ba\u8a8d\u3059\u308b<\/h2>\n<p>\u305f\u3068\u3048\u3070\u6ce8\u6587\u30c6\u30fc\u30d6\u30eb\u306b5\u884c\u3042\u308a\u3001\u30af\u30fc\u30dd\u30f3\u30b3\u30fc\u30c9\u304c2\u884c\u3060\u3051NULL\u3060\u3068\u3057\u307e\u3059\u3002<\/p>\n<table>\n<thead>\n<tr>\n<th>id<\/th>\n<th>customer_id<\/th>\n<th>coupon_code<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>1<\/td>\n<td>101<\/td>\n<td>WELCOME<\/td>\n<\/tr>\n<tr>\n<td>2<\/td>\n<td>102<\/td>\n<td>NULL<\/td>\n<\/tr>\n<tr>\n<td>3<\/td>\n<td>103<\/td>\n<td>SPRING<\/td>\n<\/tr>\n<tr>\n<td>4<\/td>\n<td>104<\/td>\n<td>NULL<\/td>\n<\/tr>\n<tr>\n<td>5<\/td>\n<td>105<\/td>\n<td>WELCOME<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<pre><code>SELECT\r\n  COUNT(*) AS total_rows,\r\n  COUNT(coupon_code) AS coupon_entered,\r\n  COUNT(DISTINCT coupon_code) AS coupon_types\r\nFROM orders;<\/code><\/pre>\n<table>\n<thead>\n<tr>\n<th>total_rows<\/th>\n<th>coupon_entered<\/th>\n<th>coupon_types<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>5<\/td>\n<td>3<\/td>\n<td>2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>`COUNT(*)`\u306f5\u884c\u3059\u3079\u3066\u3092\u6570\u3048\u307e\u3059\u3002`COUNT(coupon_code)`\u306fNULL\u306e2\u884c\u3092\u9664\u3044\u30663\u4ef6\u3001`COUNT(DISTINCT coupon_code)`\u306f\u3055\u3089\u306b\u91cd\u8907\u3059\u308b`WELCOME`\u3092\u307e\u3068\u3081\u308b\u305f\u30812\u7a2e\u985e\u3067\u3059\u3002<\/p>\n<hr>\n<h2>\u306a\u305cCOUNT(\u5217)\u306fNULL\u3092\u6570\u3048\u306a\u3044\u306e\u304b<\/h2>\n<p>`COUNT(\u5217)`\u306f\u3001\u5217\u540d\u305d\u306e\u3082\u306e\u3067\u306f\u306a\u304f\u3001\u305d\u306e\u5217\u3092\u5f0f\u3068\u3057\u3066\u5404\u884c\u3067\u8a55\u4fa1\u3057\u305f\u7d50\u679c\u3092\u6570\u3048\u307e\u3059\u3002COUNT(expression)\u304c\u5bfe\u8c61\u306b\u3059\u308b\u306e\u306f\u975eNULL\u306e\u5024\u3067\u3059\u3002\u305d\u306e\u305f\u3081\u30010\u3084\u7a7a\u6587\u5b57\u306e\u3088\u3046\u306b\u5024\u3068\u3057\u3066\u5b58\u5728\u3059\u308b\u3082\u306e\u306f\u901a\u5e38\u30ab\u30a6\u30f3\u30c8\u3055\u308c\u307e\u3059\u304c\u3001NULL\u306f\u5bfe\u8c61\u5916\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<blockquote>\n<p><strong>\u7528\u8a9e\u89e3\u8aac\uff1aNULL<\/strong><br \/>\u5024\u304c0\u3084\u7a7a\u6587\u5b57\u3067\u3042\u308b\u3053\u3068\u3067\u306f\u306a\u304f\u3001\u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u30fb\u4e0d\u660e\u3067\u3042\u308b\u3053\u3068\u3092\u8868\u3059\u7279\u5225\u306a\u72b6\u614b\u3067\u3059\u3002COUNT(\u5217)\u3067\u306fNULL\u306e\u884c\u304c\u4ef6\u6570\u306b\u542b\u307e\u308c\u307e\u305b\u3093\u3002<\/p>\n<\/blockquote>\n<p>\uff08NULL\u306e\u6bd4\u8f03\u3084IS NULL\u30fbCOALESCE\u307e\u3067\u6574\u7406\u3057\u305f\u3044\u5834\u5408\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<hr>\n<h2>GROUP BY\u3067\u306f\u30b0\u30eb\u30fc\u30d7\u3054\u3068\u306b\u540c\u3058\u30eb\u30fc\u30eb\u304c\u9069\u7528\u3055\u308c\u308b<\/h2>\n<pre><code>SELECT\r\n  customer_id,\r\n  COUNT(*) AS order_rows,\r\n  COUNT(coupon_code) AS coupon_entered\r\nFROM orders\r\nGROUP BY customer_id;<\/code><\/pre>\n<p>`GROUP BY`\u3092\u4f7f\u3063\u3066\u3082\u610f\u5473\u306f\u5909\u308f\u308a\u307e\u305b\u3093\u3002\u5404\u30b0\u30eb\u30fc\u30d7\u5185\u306e\u884c\u6570\u306f`COUNT(*)`\u3001\u305d\u306e\u30b0\u30eb\u30fc\u30d7\u5185\u3067\u7279\u5b9a\u5217\u306b\u5024\u304c\u3042\u308b\u4ef6\u6570\u306f`COUNT(\u5217)`\u3067\u3059\u3002\u96c6\u8a08\u7d50\u679c\u304c\u60f3\u5b9a\u3088\u308a\u5c11\u306a\u3044\u5834\u5408\u3001GROUP BY\u3060\u3051\u3067\u306a\u304fCOUNT\u5bfe\u8c61\u5217\u306eNULL\u3082\u78ba\u8a8d\u3057\u307e\u3059\u3002<\/p>\n<p>\uff08GROUP BY\u3068WHERE\u30fbHAVING\u306e\u5f79\u5272\u307e\u3067\u78ba\u8a8d\u3057\u305f\u3044\u5834\u5408\u306b\u3064\u3044\u3066\u306f\u300e<a href=\"https:\/\/route-zero.com\/recruit\/route\/1870\/\">GROUP BY\u4f7f\u3044\u65b9\u5b8c\u5168\u89e3\u8aac\uff5cSQL\u30a8\u30e9\u30fc\u30fbWHERE HAVING\u306e\u9055\u3044\u306f\uff1f<\/a>\u300f\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\uff09<\/p>\n<h2>LEFT JOIN\u3067\u306fCOUNT(*)\u3068COUNT(\u53f3\u8868\u306eID)\u3092\u4f7f\u3044\u5206\u3051\u308b<\/h2>\n<p>LEFT JOIN\u3067\u306f\u3001\u53f3\u5074\u306b\u4e00\u81f4\u3059\u308b\u884c\u304c\u306a\u304f\u3066\u3082\u5de6\u5074\u306e\u884c\u306f\u6b8b\u308a\u307e\u3059\u3002\u305d\u306e\u305f\u3081\u300e\u9867\u5ba2\u3054\u3068\u306e\u6ce8\u6587\u4ef6\u6570\u300f\u3092\u6570\u3048\u308b\u3068\u304d\u306b`COUNT(*)`\u3092\u4f7f\u3046\u3068\u3001\u6ce8\u6587\u304c0\u4ef6\u306e\u9867\u5ba2\u306b\u30821\u884c\u5206\u304c\u6b8b\u308b\u30b1\u30fc\u30b9\u304c\u3042\u308a\u307e\u3059\u3002\u5b9f\u969b\u306b\u4e00\u81f4\u3057\u305f\u6ce8\u6587\u3060\u3051\u3092\u6570\u3048\u305f\u3044\u306a\u3089\u3001\u53f3\u8868\u306eNULL\u306b\u306a\u3089\u306a\u3044ID\u3092COUNT\u3057\u307e\u3059\u3002<\/p>\n<pre><code>SELECT\r\n  c.id,\r\n  c.name,\r\n  COUNT(o.id) AS order_count\r\nFROM customers AS c\r\nLEFT JOIN orders AS o\r\n  ON o.customer_id = c.id\r\nGROUP BY c.id, c.name;<\/code><\/pre>\n<p>\u3053\u3053\u3067`COUNT(o.id)`\u306f\u3001\u4e00\u81f4\u3059\u308b\u6ce8\u6587\u304c\u306a\u3044\u884c\u3067\u306f`o.id`\u304cNULL\u306b\u306a\u308b\u305f\u30810\u4ef6\u306b\u306a\u308a\u307e\u3059\u3002\u300eJOIN\u5f8c\u306e\u884c\u6570\u300f\u3092\u6570\u3048\u308b\u306e\u304b\u3001\u300e\u53f3\u8868\u3067\u4e00\u81f4\u3057\u305f\u5b9f\u30c7\u30fc\u30bf\u4ef6\u6570\u300f\u3092\u6570\u3048\u308b\u306e\u304b\u3092\u5206\u3051\u3066\u8003\u3048\u308b\u306e\u304c\u30dd\u30a4\u30f3\u30c8\u3067\u3059\u3002<\/p>\n<h2>NULL\u305d\u306e\u3082\u306e\u306e\u4ef6\u6570\u3092\u6570\u3048\u308b\u65b9\u6cd5<\/h2>\n<p>NULL\u306e\u4ef6\u6570\u304c\u77e5\u308a\u305f\u3044\u5834\u5408\u306f\u3001\u7dcf\u884c\u6570\u304b\u3089\u975eNULL\u4ef6\u6570\u3092\u5f15\u304f\u3068\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n<pre><code>SELECT\r\n  COUNT(*) AS total_rows,\r\n  COUNT(coupon_code) AS non_null_rows,\r\n  COUNT(*) - COUNT(coupon_code) AS null_rows\r\nFROM orders;<\/code><\/pre>\n<p>\u6761\u4ef6\u3092\u660e\u793a\u3057\u305f\u3044\u5834\u5408\u306fCASE\u5f0f\u3067\u6570\u3048\u308b\u65b9\u6cd5\u3082\u3042\u308a\u307e\u3059\u3002<\/p>\n<pre><code>SELECT\r\n  COUNT(CASE WHEN coupon_code IS NULL THEN 1 END) AS null_rows\r\nFROM orders;<\/code><\/pre>\n<h2>COUNT\u3092\u9078\u3076\u3068\u304d\u306e\u5224\u65ad\u57fa\u6e96<\/h2>\n<ul>\n<li>\u30c6\u30fc\u30d6\u30eb\u3084\u691c\u7d22\u7d50\u679c\u306e\u5168\u884c\u6570\u3092\u77e5\u308a\u305f\u3044 \u2192 `COUNT(*)`<\/li>\n<li>\u7279\u5b9a\u9805\u76ee\u304c\u5165\u529b\u3055\u308c\u3066\u3044\u308b\u4ef6\u6570\u3092\u77e5\u308a\u305f\u3044 \u2192 `COUNT(\u5217)`<\/li>\n<li>\u91cd\u8907\u3092\u9664\u3044\u305f\u5024\u306e\u7a2e\u985e\u6570\u3092\u77e5\u308a\u305f\u3044 \u2192 `COUNT(DISTINCT \u5217)`<\/li>\n<li>LEFT JOIN\u3067\u53f3\u8868\u306e\u4e00\u81f4\u4ef6\u6570\u3092\u77e5\u308a\u305f\u3044 \u2192 \u53f3\u8868\u306e\u975eNULL\u4fdd\u8a3c\u3055\u308c\u305f\u30ad\u30fc\u3092`COUNT`<\/li>\n<li>NULL\u4ef6\u6570\u3092\u77e5\u308a\u305f\u3044 \u2192 `COUNT(*) &#8211; COUNT(\u5217)`\u307e\u305f\u306f\u6761\u4ef6\u4ed8\u304dCOUNT<\/li>\n<\/ul>\n<p>COUNT\u3067\u8ff7\u3063\u305f\u3068\u304d\u306f\u3001SQL\u306e\u66f8\u304d\u65b9\u304b\u3089\u8003\u3048\u308b\u3088\u308a\u300e\u4f55\u30921\u4ef6\u3068\u3057\u3066\u6570\u3048\u305f\u3044\u304b\u300f\u3092\u5148\u306b\u8a00\u8449\u306b\u3059\u308b\u3068\u9078\u3073\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\uff08COUNT\u4ee5\u5916\u306eSQL\u30b3\u30de\u30f3\u30c9\u3082\u7528\u9014\u5225\u306b\u78ba\u8a8d\u3057\u305f\u3044\u5834\u5408\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\u8cea\u554f<\/h2>\n<h3>COUNT(\u5217)\u306f0\u3092\u6570\u3048\u307e\u3059\u304b\uff1f<\/h3>\n<p>\u306f\u3044\u30020\u306fNULL\u3067\u306f\u306a\u304f\u5024\u306a\u306e\u3067\u3001\u5bfe\u8c61\u5217\u304c0\u3067\u3082COUNT(\u5217)\u306e\u4ef6\u6570\u306b\u542b\u307e\u308c\u307e\u3059\u3002<\/p>\n<h3>COUNT(\u5217)\u306f\u7a7a\u6587\u5b57\u3092\u6570\u3048\u307e\u3059\u304b\uff1f<\/h3>\n<p>\u7a7a\u6587\u5b57\u304cNULL\u3068\u306f\u5225\u306e\u5024\u3068\u3057\u3066\u4fdd\u5b58\u3055\u308c\u308bDB\u3067\u306f\u30ab\u30a6\u30f3\u30c8\u5bfe\u8c61\u3067\u3059\u3002\u305f\u3060\u3057DB\u88fd\u54c1\u306b\u3088\u3063\u3066\u7a7a\u6587\u5b57\u306e\u6271\u3044\u304c\u7570\u306a\u308b\u5834\u5408\u304c\u3042\u308b\u305f\u3081\u3001\u5bfe\u8c61DB\u306e\u4ed5\u69d8\u3082\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<h3>COUNT(DISTINCT \u5217)\u306fNULL\u30921\u7a2e\u985e\u3068\u3057\u3066\u6570\u3048\u307e\u3059\u304b\uff1f<\/h3>\n<p>PostgreSQL\u3084SQL Server\u306eCOUNT(DISTINCT expression)\u3067\u306fNULL\u306f\u30ab\u30a6\u30f3\u30c8\u5bfe\u8c61\u5916\u3067\u3059\u3002\u975eNULL\u306e\u91cd\u8907\u3057\u306a\u3044\u5024\u3092\u6570\u3048\u307e\u3059\u3002<\/p>\n<h3>COUNT(1)\u3068COUNT(*)\u306f\u3069\u3061\u3089\u3092\u4f7f\u3048\u3070\u3088\u3044\u3067\u3059\u304b\uff1f<\/h3>\n<p>\u884c\u6570\u3092\u6570\u3048\u308b\u610f\u56f3\u306a\u3089`COUNT(*)`\u3068\u66f8\u304f\u3068\u76ee\u7684\u304c\u660e\u78ba\u3067\u3059\u3002`COUNT(1)`\u3082\u975eNULL\u306e\u5b9a\u6570\u5f0f\u3092\u5404\u884c\u3067\u8a55\u4fa1\u3059\u308b\u305f\u3081\u884c\u6570\u3092\u6570\u3048\u308b\u5f62\u306b\u306a\u308a\u307e\u3059\u304c\u3001\u6027\u80fd\u5dee\u306fDB\u88fd\u54c1\u30fb\u30d0\u30fc\u30b8\u30e7\u30f3\u306e\u5b9f\u88c5\u306b\u4f9d\u5b58\u3059\u308b\u305f\u3081\u3001\u3053\u306e\u8a18\u4e8b\u3067\u306f\u901f\u5ea6\u76ee\u7684\u306e\u7f6e\u304d\u63db\u3048\u306f\u63a8\u5968\u3057\u307e\u305b\u3093\u3002<\/p>\n<h2>\u307e\u3068\u3081\uff1aCOUNT\u306e\u9055\u3044\u306f\u300c\u884c\u300d\u304b\u300c\u5024\u300d\u304b<\/h2>\n<ul>\n<li>`COUNT(*)`\u306f\u7d50\u679c\u30bb\u30c3\u30c8\u306e\u884c\u6570\u3092\u6570\u3048\u308b<\/li>\n<li>`COUNT(\u5217)`\u306f\u305d\u306e\u5217\u304cNULL\u3067\u306f\u306a\u3044\u884c\u3060\u3051\u3092\u6570\u3048\u308b<\/li>\n<li>`COUNT(DISTINCT \u5217)`\u306f\u975eNULL\u306e\u91cd\u8907\u3057\u306a\u3044\u5024\u3092\u6570\u3048\u308b<\/li>\n<li>GROUP BY\u3067\u3082\u5404\u30b0\u30eb\u30fc\u30d7\u5185\u3067\u540c\u3058\u30eb\u30fc\u30eb\u304c\u9069\u7528\u3055\u308c\u308b<\/li>\n<li>LEFT JOIN\u3067\u306f\u4e00\u81f4\u4ef6\u6570\u3092\u6570\u3048\u308b\u5217\u3092\u610f\u8b58\u3059\u308b<\/li>\n<\/ul>\n<p>\u4ef6\u6570\u304c\u5408\u308f\u306a\u3044SQL\u304c\u3042\u308c\u3070\u3001\u307e\u305a`COUNT(*)`\u3068`COUNT(\u5bfe\u8c61\u5217)`\u3092\u540c\u3058SELECT\u3067\u4e26\u3079\u3001NULL\u306b\u3088\u308b\u5dee\u304c\u51fa\u3066\u3044\u308b\u304b\u78ba\u8a8d\u3057\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"featured_media":6427,"template":"","meta":{"ssp_meta_title":"SQL\u306eCOUNT(*)\u3068COUNT(\u5217)\u306e\u9055\u3044\uff5cNULL\u3067\u4ef6\u6570\u304c\u5909\u308f\u308b\u7406\u7531","ssp_meta_description":"SQL\u306eCOUNT(*)\u3068COUNT(\u5217)\u306f\u3001NULL\u306e\u6271\u3044\u3067\u7d50\u679c\u304c\u5909\u308f\u308a\u307e\u3059\u3002\u5168\u884c\u6570\u30fb\u5024\u3042\u308a\u4ef6\u6570\u30fbDISTINCT\u30fbGROUP BY\u30fbLEFT 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