{"id":5277,"date":"2021-05-30T00:19:21","date_gmt":"2021-05-29T16:19:21","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=5277"},"modified":"2021-05-30T00:19:21","modified_gmt":"2021-05-29T16:19:21","slug":"mysql%e7%9a%84sql%e9%a2%84%e5%a4%84%e7%90%86prepared","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/5277","title":{"rendered":"MySQL\u7684SQL\u9884\u5904\u7406(Prepared)"},"content":{"rendered":"<p class=\"postTitle\"><a href=\"https:\/\/www.cnblogs.com\/geaozhang\/p\/9891338.html\">\u539f\u6587\u5730\u5740<\/a><\/p>\n<p>&nbsp;<\/p>\n<div class=\"clear\"><\/div>\n<div class=\"postBody\">\n<div id=\"cnblogs_post_body\" class=\"blogpost-body blogpost-body-html\">\n<blockquote><p>Prepared SQL Statement\uff1a<a href=\"https:\/\/www.cnblogs.com\/geaozhang\/p\/9891338.html#a\">SQL\u7684\u6267\u884c<\/a>\u3001<a href=\"https:\/\/www.cnblogs.com\/geaozhang\/p\/9891338.html#b\">\u9884\u7f16\u8bd1\u5904\u7406\u8bed\u6cd5<\/a>\u3001<a href=\"https:\/\/www.cnblogs.com\/geaozhang\/p\/9891338.html#c\">\u6ce8\u610f\u70b9<\/a><\/p><\/blockquote>\n<p><a name=\"a\"><\/a>\u4e00\u3001SQL \u8bed\u53e5\u7684\u6267\u884c\u5904\u7406<br \/>\n1\u3001\u5373\u65f6 SQL<br \/>\n\u4e00\u6761 SQL \u5728 DB \u63a5\u6536\u5230\u6700\u7ec8\u6267\u884c\u5b8c\u6bd5\u8fd4\u56de\uff0c\u5927\u81f4\u7684\u8fc7\u7a0b\u5982\u4e0b\uff1a<br \/>\n1. \u8bcd\u6cd5\u548c\u8bed\u4e49\u89e3\u6790\uff1b<br \/>\n2. \u4f18\u5316 SQL \u8bed\u53e5\uff0c\u5236\u5b9a\u6267\u884c\u8ba1\u5212\uff1b<br \/>\n3. \u6267\u884c\u5e76\u8fd4\u56de\u7ed3\u679c\uff1b<br \/>\n\u5982\u4e0a\uff0c\u4e00\u6761 SQL \u76f4\u63a5\u662f\u8d70\u6d41\u7a0b\u5904\u7406\uff0c\u4e00\u6b21\u7f16\u8bd1\uff0c\u5355\u6b21\u8fd0\u884c\uff0c\u6b64\u7c7b\u666e\u901a\u8bed\u53e5\u88ab\u79f0\u4f5c Immediate Statements \uff08\u5373\u65f6 SQL\uff09\u3002<br \/>\n2\u3001\u9884\u5904\u7406 SQL<br \/>\n\u4f46\u662f\uff0c\u7edd\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u67d0\u9700\u6c42\u67d0\u4e00\u6761 SQL \u8bed\u53e5\u53ef\u80fd\u4f1a\u88ab\u53cd\u590d\u8c03\u7528\u6267\u884c\uff0c\u6216\u8005\u6bcf\u6b21\u6267\u884c\u7684\u65f6\u5019\u53ea\u6709\u4e2a\u522b\u7684\u503c\u4e0d\u540c\uff08\u6bd4\u5982 select \u7684 where \u5b50\u53e5\u503c\u4e0d\u540c\uff0cupdate \u7684 set \u5b50\u53e5\u503c\u4e0d\u540c\uff0cinsert \u7684 values \u503c\u4e0d\u540c\uff09\u3002\u5982\u679c\u6bcf\u6b21\u90fd\u9700\u8981\u7ecf\u8fc7\u4e0a\u9762\u7684\u8bcd\u6cd5\u8bed\u4e49\u89e3\u6790\u3001\u8bed\u53e5\u4f18\u5316\u3001\u5236\u5b9a\u6267\u884c\u8ba1\u5212\u7b49\uff0c\u5219\u6548\u7387\u5c31\u660e\u663e\u4e0d\u884c\u4e86\u3002<br \/>\n\u6240\u8c13\u9884\u7f16\u8bd1\u8bed\u53e5\u5c31\u662f\u5c06\u6b64\u7c7b SQL \u8bed\u53e5\u4e2d\u7684\u503c\u7528\u5360\u4f4d\u7b26\u66ff\u4ee3\uff0c\u53ef\u4ee5\u89c6\u4e3a\u5c06 SQL \u8bed\u53e5\u6a21\u677f\u5316\u6216\u8005\u8bf4\u53c2\u6570\u5316\uff0c\u4e00\u822c\u79f0\u8fd9\u7c7b\u8bed\u53e5\u53ebPrepared Statements\u3002<br \/>\n\u9884\u7f16\u8bd1\u8bed\u53e5\u7684\u4f18\u52bf\u5728\u4e8e\u5f52\u7eb3\u4e3a\uff1a\u4e00\u6b21\u7f16\u8bd1\u3001\u591a\u6b21\u8fd0\u884c\uff0c\u7701\u53bb\u4e86\u89e3\u6790\u4f18\u5316\u7b49\u8fc7\u7a0b\uff1b\u6b64\u5916\u9884\u7f16\u8bd1\u8bed\u53e5\u80fd\u9632\u6b62 SQL \u6ce8\u5165\u3002<br \/>\n\u6ce8\u610f\uff1a<br \/>\n\u867d\u7136\u53ef\u80fd\u662f\u901a\u8fc7\u9884\u5904\u7406 SQL \u7684\u65b9\u5f0f\u4e00\u5b9a\u7a0b\u5ea6\u7684\u63d0\u9ad8\u4e86\u6548\u7387\uff0c\u4f46\u662f\u5bf9\u4e8e\u4f18\u5316\u800c\u8a00\uff0c\u6700\u4f18\u7684\u6267\u884c\u8ba1\u5212\u4e0d\u662f\u5149\u9760 SQL \u8bed\u53e5\u7684\u6a21\u677f\u5316\u6765\u5b9e\u73b0\u7684\uff0c\u5f80\u5f80\u8fd8\u662f\u9700\u8981\u901a\u8fc7\u5177\u4f53\u503c\u6765\u9884\u4f30\u51fa\u6210\u672c\u4ee3\u4ef7\u3002<\/p>\n<p>&nbsp;<\/p>\n<p><a name=\"b\"><\/a>\u4e8c\u3001Prepared SQL Statement Syntax<br \/>\nMySQL \u5b98\u65b9\u5c06 prepare\u3001execute\u3001deallocate \u7edf\u79f0\u4e3a PREPARE STATEMENT\u3002\u7ffb\u8bd1\u4e5f\u5c31\u4e60\u60ef\u7684\u79f0\u5176\u4e3a\u9884\u5904\u7406\u8bed\u53e5\u3002<br \/>\nMySQL \u9884\u5904\u7406\u8bed\u53e5\u7684\u652f\u6301\u7248\u672c\u8f83\u65e9\uff0c\u6240\u4ee5\u6211\u4eec\u76ee\u524d\u666e\u904d\u4f7f\u7528\u7684 MySQL \u7248\u672c\u90fd\u662f\u652f\u6301\u8fd9\u4e00\u8bed\u6cd5\u7684\u3002<br \/>\n\u8bed\u6cd5\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<pre># \u5b9a\u4e49\u9884\u5904\u7406\u8bed\u53e5\r\nPREPARE stmt_name FROM preparable_stmt;\r\n# \u6267\u884c\u9884\u5904\u7406\u8bed\u53e5\r\nEXECUTE stmt_name [USING @var_name [, @var_name] ...];\r\n# \u5220\u9664(\u91ca\u653e)\u5b9a\u4e49\r\n{DEALLOCATE | DROP} PREPARE stmt_name;<\/pre>\n<\/div>\n<p>1\u3001\u5229\u7528\u5b57\u7b26\u4e32\u5b9a\u4e49\u9884\u5904\u7406 SQL\u00a0(\u76f4\u89d2\u4e09\u89d2\u5f62\u8ba1\u7b97)<\/p>\n<div class=\"cnblogs_code\">\n<pre>mysql&gt; PREPARE stmt1 FROM 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';\r\nQuery OK, 0 rows affected (0.00 sec)\r\nStatement prepared\r\n\r\nmysql&gt; SET @a = 3;\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; SET @b = 4;                                                   \r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; EXECUTE stmt1 USING @a, @b;\r\n+------------+\r\n| hypotenuse |\r\n+------------+\r\n|          5 |\r\n+------------+\r\n1 row in set (0.00 sec)\r\n\r\nmysql&gt; DEALLOCATE PREPARE stmt1;                                     \r\nQuery OK, 0 rows affected (0.00 sec)<\/pre>\n<\/div>\n<p>2\u3001\u5229\u7528\u53d8\u91cf\u5b9a\u4e49\u9884\u5904\u7406 SQL\u00a0(\u76f4\u89d2\u4e09\u89d2\u5f62\u8ba1\u7b97)<\/p>\n<div class=\"cnblogs_code\">\n<pre>mysql&gt; SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; PREPARE stmt2 FROM @s;\r\nQuery OK, 0 rows affected (0.00 sec)\r\nStatement prepared\r\n\r\nmysql&gt; SET @c = 6;\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; SET @d = 8;\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; EXECUTE stmt2 USING @c, @d;\r\n+------------+\r\n| hypotenuse |\r\n+------------+\r\n|         10 |\r\n+------------+\r\n1 row in set (0.00 sec)\r\n\r\nmysql&gt; DEALLOCATE PREPARE stmt2;\r\nQuery OK, 0 rows affected (0.00 sec)<\/pre>\n<\/div>\n<p>3\u3001\u89e3\u51b3\u65e0\u6cd5\u4f20\u53c2\u95ee\u9898<br \/>\n\u6211\u4eec\u77e5\u9053\uff0c\u5bf9\u4e8e LIMIT \u5b50\u53e5\u4e2d\u7684\u503c\uff0c\u5fc5\u987b\u662f\u5e38\u91cf\uff0c\u4e0d\u5f97\u4f7f\u7528\u53d8\u91cf\uff0c\u4e5f\u5c31\u662f\u8bf4\u4e0d\u80fd\u4f7f\u7528\uff1aSELECT * FROM TABLE LIMIT @skip, @numrows; \u5982\u6b64\uff0c\u5c31\u53ef\u4ee5\u662f\u7528 PREPARE \u8bed\u53e5\u89e3\u51b3\u6b64\u95ee\u9898\u3002<\/p>\n<div class=\"cnblogs_code\">\n<pre>mysql&gt; SET @skip = 100; SET @numrows = 3;\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; SELECT * FROM t1 LIMIT @skip, @numrows;\r\nERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@skip, @numrows' at line 1\r\n\r\nmysql&gt; PREPARE stmt3 FROM \"SELECT * FROM t1 LIMIT ?, ?\";\r\nQuery OK, 0 rows affected (0.00 sec)\r\nStatement prepared\r\n\r\nmysql&gt; EXECUTE stmt3 USING @skip, @numrows;\r\n+-----+--------+\r\n| a   | filler |\r\n+-----+--------+\r\n| 100 | filler |\r\n| 101 | filler |\r\n| 102 | filler |\r\n+-----+--------+\r\n3 rows in set (0.00 sec)\r\n\r\nmysql&gt; DEALLOCATE PREPARE stmt3;\r\nQuery OK, 0 rows affected (0.00 sec)<\/pre>\n<\/div>\n<p>\u5982\u6b64\u4e00\u6765\uff0c\u7ed3\u54082\u4e2d\u4ecb\u7ecd\u7684\u5229\u7528\u53d8\u91cf\u5b9a\u4e49\u9884\u5904\u7406 SQL \u4e5f\u5c31\u57fa\u672c\u89e3\u51b3\u4e86\u4f20\u53c2\u65f6\u8bed\u6cd5\u62a5\u9519\u95ee\u9898\u4e86\uff0c\u7c7b\u4f3c\u7684\uff1a\u7528\u53d8\u91cf\u4f20\u53c2\u505a\u8868\u540d\u65f6\uff0cMySQL \u4f1a\u628a\u53d8\u91cf\u540d\u5f53\u505a\u8868\u540d\uff0c\u8fd9\u6837\u65e2\u4e0d\u662f\u672c\u610f\uff0c\u4e5f\u4f1a\u662f\u8bed\u6cd5\u9519\u8bef\uff0c\u5728 SQL Server \u7684\u89e3\u51b3\u529e\u6cd5\u662f\u5229\u7528\u5b57\u7b26\u4e32\u62fc\u63a5\u7a7f\u63d2\u53d8\u91cf\u8fdb\u884c\u4f20\u53c2\uff0c\u518d\u5c06\u6574\u6761 SQL \u8bed\u53e5\u4f5c\u4e3a\u53d8\u91cf\uff0c\u6700\u540e\u662f\u7528\u00a0sp_executesql\u00a0\u8c03\u7528\u8be5\u62fc\u63a5 SQL \u6267\u884c\uff0c\u800c Prepared SQL Statement \u53ef\u8c13\u5f02\u66f2\u540c\u5de5\u4e4b\u5999\u3002<\/p>\n<div class=\"cnblogs_code\">\n<pre>mysql&gt; SET @table = 't2';\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; SET @s = CONCAT('SELECT * FROM ', @table);\r\nQuery OK, 0 rows affected (0.00 sec)\r\n\r\nmysql&gt; PREPARE stmt4 FROM @s;\r\nQuery OK, 0 rows affected (0.00 sec)\r\nStatement prepared\r\n\r\nmysql&gt; EXECUTE stmt4;\r\n+------+-------+-------+\r\n| id   | score | grade |\r\n+------+-------+-------+\r\n|    1 |    99 | A     |\r\n|    2 |    81 | B     |\r\n|    3 |    55 | D     |\r\n|    4 |    69 | C     |\r\n+------+-------+-------+\r\n4 rows in set (0.00 sec)\r\n\r\nmysql&gt; DROP PREPARE stmt4;\r\nQuery OK, 0 rows affected (0.00 sec)<\/pre>\n<\/div>\n<p>&nbsp;<\/p>\n<p><a name=\"c\"><\/a>\u4e09\u3001\u9884\u5904\u7406 SQL \u4f7f\u7528\u6ce8\u610f\u70b9<br \/>\n1\u3001stmt_name \u4f5c\u4e3a preparable_stmt \u7684\u63a5\u6536\u8005\uff0c\u552f\u4e00\u6807\u8bc6\uff0c\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u3002<br \/>\n2\u3001preparable_stmt \u8bed\u53e5\u4e2d\u7684\u00a0? \u662f\u4e2a\u5360\u4f4d\u7b26\uff0c\u6240\u4ee3\u8868\u7684\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u4e0d\u9700\u8981\u5c06 ? \u7528\u5f15\u53f7\u5305\u542b\u8d77\u6765\u3002<br \/>\n3\u3001\u5b9a\u4e49\u4e00\u4e2a\u5df2\u5b58\u5728\u7684 stmt_name \uff0c\u539f\u6709\u7684\u5c06\u88ab\u7acb\u5373\u91ca\u653e\uff0c\u7c7b\u4f3c\u4e8e\u53d8\u91cf\u7684\u91cd\u65b0\u8d4b\u503c\u3002<br \/>\n4\u3001PREPARE stmt_name \u7684\u4f5c\u7528\u57df\u662fsession\u7ea7<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/img2018.cnblogs.com\/blog\/1113510\/201811\/1113510-20181101192302151-157684852.png\" alt=\"\" \/><br \/>\n\u53ef\u4ee5\u901a\u8fc7\u00a0max_prepared_stmt_count\u00a0\u53d8\u91cf\u6765\u63a7\u5236\u5168\u5c40\u6700\u5927\u7684\u5b58\u50a8\u7684\u9884\u5904\u7406\u8bed\u53e5\u3002<\/p>\n<div class=\"cnblogs_code\">\n<pre>mysql&gt; show variables like 'max_prepared%';\r\n+-------------------------+-------+\r\n| Variable_name           | Value |\r\n+-------------------------+-------+\r\n| max_prepared_stmt_count | 16382 |\r\n+-------------------------+-------+\r\n1 row in set (0.00 sec)<\/pre>\n<\/div>\n<p>\u9884\u5904\u7406\u7f16\u8bd1 SQL \u662f\u5360\u7528\u8d44\u6e90\u7684\uff0c\u6240\u4ee5\u5728\u4f7f\u7528\u540e\u6ce8\u610f\u53ca\u65f6\u4f7f\u7528 DEALLOCATE PREPARE \u91ca\u653e\u8d44\u6e90\uff0c\u8fd9\u662f\u4e00\u4e2a\u597d\u4e60\u60ef\u3002<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u539f\u6587\u5730\u5740 &nbsp; Prepared<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[118],"class_list":["post-5277","post","type-post","status-publish","format-standard","hentry","tag-02-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/5277","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=5277"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/5277\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=5277"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=5277"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=5277"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}