{"id":7567,"date":"2024-08-30T20:32:22","date_gmt":"2024-08-30T11:32:22","guid":{"rendered":"https:\/\/techmania.jp\/blog\/?p=7567"},"modified":"2025-08-22T15:23:06","modified_gmt":"2025-08-22T06:23:06","slug":"sql-cast","status":"publish","type":"post","link":"https:\/\/techmania.jp\/blog\/sql-cast\/","title":{"rendered":"\u3010SQL\u3011CAST\u3067\u30c7\u30fc\u30bf\u578b\u3092\u5909\u66f4\u3059\u308b\uff01\u4f7f\u3044\u65b9\u3084\u6ce8\u610f\u70b9\u3092\u89e3\u8aac"},"content":{"rendered":"

\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u3092\u64cd\u4f5c\u3059\u308b\u4e0a\u3067\u3001<\/span>\u30c7\u30fc\u30bf\u578b\u3092\u5909\u63db\u3059\u308b\u3053\u3068\u304c\u6c42\u3081\u3089\u308c\u308b\u3053\u3068\u3082\u591a\u3044\u3068\u601d\u3044\u307e\u3059\u3002\u305d\u3053\u3067\u5f79\u7acb\u3064\u306e\u304c\u300cCAST\u300d\u95a2\u6570\u3067\u3059\u3002<\/span><\/span>CAST\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u305f\u3068\u3048\u3070\u3001\u6587\u5b57\u5217\u3092\u65e5\u4ed8\u306e\u30c7\u30fc\u30bf\u5f62\u5f0f\u306b\u5909\u66f4\u3059\u308b\u3068\u3044\u3063\u305f\u3053\u3068\u304c\u7c21\u5358\u306b\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002\u672c\u8a18\u4e8b\u3067\u306f\u30c7\u30fc\u30bf\u578b\u306e\u7a2e\u985e\u3084CAST\u3067\u30c7\u30fc\u30bf\u578b\u3092\u5909\u63db\u3059\u308b\u65b9\u6cd5\u3092\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3092\u7528\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n

CAST\u3068\u306f<\/h2>\n\n\n

SQL\u306eCAST\u3068\u306f\u3001\u30c7\u30fc\u30bf\u578b\u3092\u5909\u66f4\u3059\u308b\u306e\u306b\u7528\u3044\u3089\u308c\u308b\u95a2\u6570\u3067\u3059\u3002CAST\u95a2\u6570\u3092\u7528\u3044\u308b\u3053\u3068\u3067\u3042\u308b\u30c7\u30fc\u30bf\u578b\u306e\u5024\u3092\u5225\u306e\u30c7\u30fc\u30bf\u578b\u306b\u5909\u63db\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u305f\u3068\u3048\u3070\u3001\u6587\u5b57\u5217\u578b\u306e\u5024\u3092\u65e5\u4ed8\u578b\u3084\u6570\u5024\u578b\u306b\u5909\u63db\u3059\u308b\u3068\u3044\u3063\u305f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n

\u305d\u3082\u305d\u3082\u30c7\u30fc\u30bf\u578b\u3068\u306f<\/h2>\n\n\n

SQL\u306b\u9650\u3089\u305a\u3001\u30d7\u30ed\u30b0\u30e9\u30e0\u4e0a\u3067\u9069\u5207\u306b\u30c7\u30fc\u30bf\u3092\u53d6\u308a\u6271\u3046\u4e0a\u3067\u3001\u30c7\u30fc\u30bf\u306e\u5f62\u5f0f\u3092\u5b9a\u7fa9\u3059\u308b\u300c\u30c7\u30fc\u30bf\u578b\u300d\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n

\u30c7\u30fc\u30bf\u578b\u3068\u306f\u3001\u30b3\u30f3\u30d4\u30e5\u30fc\u30bf\u4e0a\u3067\u30c7\u30fc\u30bf\u3092\u5224\u5225\u3059\u308b\u306e\u306b\u7528\u3044\u3089\u308c\u308b\u30c7\u30fc\u30bf\u5f62\u5f0f\u306e\u7a2e\u985e\u3092\u6307\u3057\u307e\u3059\u3002\u30d7\u30ed\u30b0\u30e9\u30e0\u3084\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u4e0a\u3067\u5909\u6570\u3084\u30c7\u30fc\u30bf\u306e\u30e1\u30e2\u30ea\u9818\u57df\u306b\u5272\u308a\u5f53\u3066\u308b\u969b\u306b\u3001\u30c7\u30fc\u30bf\u306e\u7a2e\u985e\u3092\u793a\u3059\u306e\u306b\u7528\u3044\u3089\u308c\u307e\u3059\u3002\u30c7\u30fc\u30bf\u578b\u306e\u7a2e\u985e\u306b\u3088\u3063\u3066\u3001\u30c7\u30fc\u30bf\u304c\u5224\u5225\u3055\u308c\u3001\u9069\u5207\u306a\u51e6\u7406\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n

\u3042\u306a\u305f\u306e\u3054\u5e0c\u671b\u306b\u6cbf\u3063\u305f\u6848\u4ef6\u304c\u5fc5\u305a<\/span>\u898b\u3064\u304b\u308a\u307e\u3059
\u3010\u30d5\u30ea\u30fc\u30e9\u30f3\u30b9\u5411\u3051\u3011\u9ad8\u53ce\u5165<\/span>\u30fb<\/span>\u597d\u5f85\u9047<\/span>\u306e\u6848\u4ef6\u3092\u3054\u7d39\u4ecb<\/span>\n<\/p><\/a>\n<\/div>\n\n

\"TECH<\/a>\n<\/div>\n\n
\n

\u226b\u307e\u305a\u306f\u7c21\u535860<\/span>\u79d2\u3067\u7121\u6599\u304a\u554f\u3044\u5408\u308f\u305b<\/span>\u304b\u3089\u226a\n<\/p><\/a>\n<\/div>\n\n\n\n

SQL\u306b\u304a\u3051\u308b\u30c7\u30fc\u30bf\u578b\u306e\u7a2e\u985e<\/h2>\n\n\n

SQL\u306b\u304a\u3051\u308b\u30c7\u30fc\u30bf\u578b\u306e\u7a2e\u985e\u306b\u3064\u3044\u3066\u4ee3\u8868\u7684\u306a\u3082\u306e\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n

\u6570\u5024\u578b<\/strong><\/p>\n\n\n

\u30c7\u30fc\u30bf\u578b<\/strong><\/td>\u6982\u8981<\/strong><\/td>\u7bc4\u56f2<\/strong><\/td><\/tr>
INTEGER<\/td>\u6574\u6570\u578b<\/td>-2,147,483,648\uff5e2,147,483,647<\/td><\/tr>
FLOAT<\/td>\u6d6e\u52d5\u5c0f\u6570\u70b9\u578b<\/td>-3.402823466E+38\uff5e-1.175494351E-38\u30010\u30011.175494351E-38\uff5e3.402823466E+38<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n

\u6587\u5b57\u5217\u578b<\/strong><\/p>\n\n\n

\u30c7\u30fc\u30bf\u578b<\/strong><\/td>\u6982\u8981<\/strong><\/td>\u6700\u5927\u683c\u7d0d\u53ef\u80fd\u6587\u5b57\u6570\u30fb\u30b5\u30a4\u30ba\u6570<\/strong><\/td><\/tr>
CHAR<\/td>\u56fa\u5b9a\u9577\u6587\u5b57\u5217\u578b<\/td>1\u304b\u3089255\u6587\u5b57\u307e\u3067\u6307\u5b9a\u53ef\u80fd<\/td><\/tr>
VARCHAR<\/td>\u53ef\u5909\u9577\u6587\u5b57\u5217\u578b<\/td>\u7d0465,535\u6587\u5b57\u307e\u3067\u6307\u5b9a\u53ef\u80fd<\/td><\/tr>
TEXT<\/td>\u5927\u6587\u5b57\u5217\u578b<\/td>\u7d042GB\u307e\u3067\u306e\u30c6\u30ad\u30b9\u30c8\u30c7\u30fc\u30bf\u3092\u683c\u7d0d\u53ef\u80fd<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n

\u203b\u6700\u5927\u9577\u30fb\u6700\u5927\u30b5\u30a4\u30ba\u306f\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u7a2e\u985e\u306b\u3088\u3063\u3066\u7570\u306a\u308a\u307e\u3059\u3002<\/p>\n

\u65e5\u4ed8\u578b<\/strong><\/p>\n\n\n

\u30c7\u30fc\u30bf\u578b<\/strong><\/td>\u6982\u8981<\/strong><\/td>\u683c\u7d0d\u5185\u5bb9<\/strong><\/td><\/tr>
DATE<\/td>\u65e5\u4ed8\u578b<\/td>\u65e5\u4ed8\u3092\u683c\u7d0d\u3059\u308b\uff08\u5e74\u3001\u6708\u3001\u65e5\uff09<\/td><\/tr>
TIME<\/td>\u6642\u523b\u578b<\/td>\u6642\u523b\u3092\u683c\u7d0d\u3059\u308b\uff08\u6642\u3001\u5206\u3001\u79d2\uff09<\/td><\/tr>
DATETIME<\/td>\u65e5\u4ed8\u6642\u523b\u578b<\/td>\u65e5\u4ed8\u3068\u6642\u523b\u3092\u683c\u7d0d\u3059\u308b<\/td><\/tr>
TIMESTAMP<\/td>\u65e5\u4ed8\u6642\u523b\u578b<\/td>\u4e00\u610f\u306e\u30bf\u30a4\u30e0\u30b9\u30bf\u30f3\u30d7\u3092\u683c\u7d0d\u3057\u3001\u30c7\u30fc\u30bf\u306e\u8ffd\u52a0\u30fb\u66f4\u65b0\u6642\u306b\u81ea\u52d5\u3067\u751f\u6210\u30fb\u66f4\u65b0\u3055\u308c\u308b<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n

\u30d0\u30a4\u30ca\u30ea\u578b<\/strong><\/p>\n\n\n

\u30c7\u30fc\u30bf\u578b<\/strong><\/td>\u6982\u8981<\/strong><\/td>\u683c\u7d0d\u5185\u5bb9<\/strong><\/td><\/tr>
BINARY<\/td>\u56fa\u5b9a\u9577\u30d0\u30a4\u30ca\u30ea\u578b<\/td>\u56fa\u5b9a\u9577\u306e\u30d0\u30a4\u30ca\u30ea\u30c7\u30fc\u30bf\u3092\u683c\u7d0d\u3059\u308b<\/td><\/tr>
VARBINARY<\/td>\u53ef\u5909\u9577\u30d0\u30a4\u30ca\u30ea\u578b<\/td>\u53ef\u5909\u9577\u306e\u30d0\u30a4\u30ca\u30ea\u30c7\u30fc\u30bf\u3092\u683c\u7d0d\u3059\u308b<\/td><\/tr>
BLOB<\/td>\u5927\u30d0\u30a4\u30ca\u30ea\u578b<\/td>\u753b\u50cf\u3001\u52d5\u753b\u3001\u97f3\u58f0\u306a\u3069\u3001\u5927\u304d\u306a\u30d0\u30a4\u30ca\u30ea\u30c7\u30fc\u30bf\uff08Binary Large Object\uff09\u3092\u683c\u7d0d\u3059\u308b<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n

\u203b\u6700\u5927\u683c\u7d0d\u53ef\u80fd\u30b5\u30a4\u30ba\u6570\u306f\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u7a2e\u985e\u306b\u3088\u3063\u3066\u7570\u306a\u308a\u307e\u3059\u3002<\/p>\n

\u8ad6\u7406\u578b<\/strong><\/p>\n\n\n

\u30c7\u30fc\u30bf\u578b<\/strong><\/td>\u6982\u8981<\/strong><\/td>\u683c\u7d0d\u5185\u5bb9<\/strong><\/td><\/tr>
BOOLEAN<\/td>\u30d6\u30fc\u30eb\u578b<\/td>\u771f\uff08TRUE\uff09\u307e\u305f\u306f\u507d\uff08FALSE\uff09\u3001\u672a\u5b9a\u7fa9\uff08NULL\uff09\u306e\u5024\u3092\u683c\u7d0d\u3059\u308b<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n

\u203b\u6319\u52d5\u306f\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u7a2e\u985e\u306b\u3088\u3063\u3066\u7570\u306a\u308a\u307e\u3059\u3002<\/p>\n

\u3053\u308c\u3089\u306e\u30c7\u30fc\u30bf\u578b\u306f\u3001\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u7a2e\u985e\u306b\u3088\u3063\u3066\u540d\u524d\u3001\u30b5\u30dd\u30fc\u30c8\u7bc4\u56f2\u3001\u6319\u52d5\u306a\u3069\u304c\u7570\u306a\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002\u30c7\u30fc\u30bf\u578b\u306f\u30c7\u30fc\u30bf\u306e\u7279\u6027\u3068\u7528\u9014\u306b\u5408\u3063\u305f\u3082\u306e\u3092\u9078\u629e\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n

CAST\u3067\u30c7\u30fc\u30bf\u578b\u3092\u5909\u66f4\u3059\u308b\u65b9\u6cd5<\/h2>\n\n\n

\u3010\u57fa\u672c\u69cb\u6587\u3011<\/strong><\/p>\n\n\n

CAST\uff08\u5909\u63db\u3059\u308b\u5024\u3084\u30ab\u30e9\u30e0 AS \u5909\u63db\u3057\u305f\u3044\u30c7\u30fc\u30bf\u578b\uff09<\/strong><\/code><\/pre>\n\n\n
\u4e92\u63db\u6027\u306e\u3042\u308b\u30c7\u30fc\u30bf\u578b\u306b\u5bfe\u3057\u3066\u306e\u307fCAST\u3092\u9069\u7528\u3067\u304d\u307e\u3059\u3002\u306a\u304a\u3001CAST\u306f\u3001WHERE\u53e5\u306a\u3069\u306e\u4e00\u822c\u7684\u306a\u5f0f\u304c\u8a31\u53ef\u3055\u308c\u308b\u5927\u62b5\u306e\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u3067\u8a31\u53ef\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n
\u6b63\u5e38\u306b\u5909\u63db\u304c\u884c\u308f\u308c\u308b\u3088\u3046\u9069\u5207\u306a\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0\u304c\u5fc5\u8981\u306b\u306a\u308a\u307e\u3059\u3002\u307e\u305f\u3001\u30c7\u30fc\u30bf\u306e\u5927\u304d\u3055\u3084\u5185\u5bb9\u306a\u3069\u306b\u3088\u3063\u3066\u3001\u30c7\u30fc\u30bf\u306e\u640d\u5931\u3084\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3059\u308b\u5834\u5408\u3082\u3042\u308b\u305f\u3081\u6ce8\u610f\u3057\u307e\u3057\u3087\u3046\u3002<\/p>\n
\u3053\u3053\u304b\u3089\u306f\u5177\u4f53\u7684\u306a\u30b3\u30fc\u30c9\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n\n\n
1\uff0e\u6587\u5b57\u5217\u578b\u3092INTEGER\uff08\u6570\u5024\u578b\uff09\u306b\u5909\u63db\u3059\u308b\u5834\u5408<\/h3>\n\n\n
\u3010SQL\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
SELECT CAST(id AS INTEGER) FROM student<\/strong>;<\/code><\/pre>\n\n\n
\u30c7\u30fc\u30bf\u578b\u306e\u5909\u66f4\u306f\u91cd\u8981\u306a\u4f5c\u696d\u3067\u3042\u308b\u305f\u3081\u3001\u614e\u91cd\u306b\u884c\u3046\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u307e\u305a\u3001\u30c6\u30b9\u30c8\u74b0\u5883\u3067\u8a66\u3057\u3066\u304b\u3089\u672c\u756a\u74b0\u5883\u3067\u5b9f\u884c\u3059\u308b\u306e\u304c\u671b\u307e\u3057\u3044\u3067\u3059\u3002<\/p>\n\n\n
2\uff0e\u6570\u5024\u578b\u3092\u6587\u5b57\u5217\u578b\u306b\u5909\u63db\u3059\u308b\u5834\u5408<\/h3>\n\n\n
\u3010SQL\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
SELECT CAST(100 AS VARCHAR(10))+'A';<\/strong><\/code><\/pre>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n
100A<\/strong><\/code><\/pre>\n\n\n
\u3010SQL\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
SELECT CAST(100 AS CHAR(10))+'A';<\/strong><\/code><\/pre>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n
100      A<\/strong><\/code><\/pre>\n\n\n
CHAR\uff08\u56fa\u5b9a\u9577\u6587\u5b57\u5217\u578b\uff09\u3060\u3068\u5909\u63db\u3055\u308c\u305f\u3053\u3068\u304c\u308f\u304b\u308a\u3084\u3059\u3044\u3067\u3059\u306d\u3002<\/p>\n\n\n
3\uff0e\u6587\u5b57\u5217\u578b\u3092\u65e5\u4ed8\u578b\u306b\u5909\u63db\u3059\u308b\u5834\u5408<\/h3>\n\n\n
\u6587\u5b57\u5217\u3092\u305d\u308c\u305e\u308c\u65e5\u4ed8\u578b\u300cDATE\u300d\u3001\u65e5\u4ed8\u6642\u9593\u578b\u300cDATETIME\u300d\u306b\u5909\u63db\u3057\u307e\u3059\u3002<\/p>\n
\u3010SQL\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
SELECT CAST('2024-08-27' AS DATE);<\/strong><\/code><\/pre>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n
2024\/08\/27<\/strong><\/code><\/pre>\n\n\n
\u3010SQL\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
SELECT CAST('2024-08-27 19:22:30' AS DATETIME);<\/strong><\/code><\/pre>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n
2024\/08\/27 19:22:30<\/strong><\/code><\/pre>\n\n\n
CHAR\uff08\u56fa\u5b9a\u9577\u6587\u5b57\u5217\u578b\uff09\u3060\u3068\u5909\u63db\u3055\u308c\u305f\u3053\u3068\u304c\u308f\u304b\u308a\u3084\u3059\u3044\u3067\u3059\u306d\u3002<\/p>\n
\u65e5\u4ed8\u6642\u9593\u578b\u300cDATETIME\u300d\u5909\u63db\u3067\u6642\u9593\u90e8\u5206\u3092\u6307\u5b9a\u3057\u306a\u3044\u3068\u300c00:00:00\u300d\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n
\u6ce8\u610f\u70b9<\/h2>\n\n\n\n
\u7570\u306a\u308b\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u306e\u5834\u5408<\/h3>\n\n\n
CAST\u95a2\u6570\u3067\u6587\u5b57\u5217\u578b\u306e\u5024\u3092DATETIME\u578b\u306b\u5909\u63db\u3059\u308b\u3053\u3068\u3067\u65e5\u4ed8\u3068\u6642\u523b\u3068\u3057\u3066\u6271\u3048\u307e\u3059\u3002\u3053\u306e\u969b\u3001\u6a19\u6e96\u7684\u306a\u65e5\u4ed8\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u3067\u3042\u308b\u5834\u5408\u306f\u300cDATETIME\u300d\u3067\u554f\u984c\u3042\u308a\u307e\u305b\u3093\u304c\u3001\u7570\u306a\u308b\u5f62\u5f0f\u306e\u65e5\u4ed8\u6587\u5b57\u5217\u3092\u5909\u63db\u3059\u308b\u5834\u5408\u306f\u3001\u300cSTR_TO_DATE\u300d\u95a2\u6570\u306a\u3069\u3092\u4f7f\u7528\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/span><\/span><\/p>\n
\u305f\u3068\u3048\u3070\u3001\u65e5\u4ed8\u304c\u300c2024\/08\/27 19:22:30\u300d\u3068\u3044\u3046\u5f62\u5f0f\u3067\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u5834\u5408\u306f\u6b21\u306e\u3088\u3046\u306b\u8a18\u8ff0\u3057\u307e\u3059\u3002<\/span><\/p>\n\n\n
SELECT date_a,STR_TO_DATE(date_a,'%Y\/%m\/%d %H:%i:%s') AS datetime FROM sample;<\/strong><\/code><\/pre>\n\n\n\n
\u30c6\u30fc\u30d6\u30eb\u306e\u30c7\u30fc\u30bf\u578b\u5909\u66f4<\/h3>\n\n\n
\u5143\u306e\u30c6\u30fc\u30d6\u30eb\u306e\u30c7\u30fc\u30bf\u578b\u306f\u5909\u66f4\u3055\u308c\u306a\u3044\u305f\u3081\u30c6\u30fc\u30d6\u30eb\u81ea\u4f53\u306e\u30c7\u30fc\u30bf\u578b\u3092\u5909\u66f4\u3059\u308b\u5834\u5408\u306f\u3001\u300cALTER TABLE\u300d\u6587\u3092\u4f7f\u7528\u3057\u307e\u3059\u3002<\/p>\n
\u3010\u57fa\u672c\u69cb\u6587\u3011<\/strong><\/p>\n\n\n
ALTER TABLE \u30c6\u30fc\u30d6\u30eb\u540d ALTER COLUMN \u30ab\u30e9\u30e0\u540d \u5909\u66f4\u3057\u305f\u3044\u30c7\u30fc\u30bf\u578b<\/strong><\/code><\/pre>\n\n\n
\u305f\u3068\u3048\u3070\u3001\u300c\u751f\u5f92\uff08student\uff09\u300d\u30c6\u30fc\u30d6\u30eb\u306e\u300cID\uff08id\uff09\u300d\u30ab\u30e9\u30e0\u306e\u30c7\u30fc\u30bf\u578b\u3092\u6587\u5b57\u5217\u578b\u304b\u3089\u6570\u5024\u578b\uff08INTEGER\uff09\u306b\u5909\u66f4\u3059\u308b\u5834\u5408\u306f\u3001\u6b21\u306e\u3088\u3046\u306b\u8a18\u8ff0\u3057\u307e\u3059\u3002<\/span><\/p>\n
\u3010SQL\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
ALTER TABLE student ALTER COLUMN id INTEGER;<\/strong><\/code><\/pre>\n\n\n\n
\u307e\u3068\u3081<\/h2>\n\n\n
CAST\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u30af\u30a8\u30ea\u3084\u8a08\u7b97\u304c\u3057\u3084\u3059\u304f\u306a\u308a\u3001\u30c7\u30fc\u30bf\u306e\u51e6\u7406\u3084\u5206\u6790\u3082\u52b9\u7387\u7684\u306b\u884c\u3048\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002\u5b9f\u52d9\u3067\u3082\u6570\u5024\u304b\u3089\u6587\u5b57\u5217\u3078\u306e\u5909\u63db\u3001\u6587\u5b57\u5217\u304b\u3089\u6570\u5024\u3078\u306e\u5909\u63db\u3092\u4f7f\u3046\u6a5f\u4f1a\u306f\u591a\u304f\u3042\u308a\u307e\u3059\u3002\u4f7f\u7528\u3059\u308b\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u3084\u30c7\u30fc\u30bf\u306b\u5408\u308f\u305b\u3066CAST\u95a2\u6570\u3092\u6d3b\u7528\u3057\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n
SQL\u95a2\u9023\u8a18\u4e8b<\/h2>\n\n\n
\n