{"id":128,"date":"2023-07-21T13:22:57","date_gmt":"2023-07-21T05:22:57","guid":{"rendered":"https:\/\/jiachen.de.cool\/blog\/?p=128"},"modified":"2023-07-21T13:25:00","modified_gmt":"2023-07-21T05:25:00","slug":"%e5%ad%97%e7%ac%a6%e4%b8%b2%e6%88%aa%e5%8f%96%e4%b8%8e%e6%9b%bf%e6%8d%a2%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/jiachen.de.cool\/blog\/2023\/07\/21\/%e5%ad%97%e7%ac%a6%e4%b8%b2%e6%88%aa%e5%8f%96%e4%b8%8e%e6%9b%bf%e6%8d%a2%e5%87%bd%e6%95%b0\/","title":{"rendered":"\u5b57\u7b26\u4e32\u622a\u53d6\u4e0e\u66ff\u6362\u51fd\u6570"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">1\u3001\u4ece\u5de6\u8fb9\u6216\u53f3\u8fb9\u622a\u53d6\u5b50\u5b57\u7b26\u4e32<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>left(str,num);<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>right(str,num);<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd4\u56de\u5b57\u7b26\u4e32str\u4e2d\u5305\u542b\u524dnum\u4e2a\u5b57\u6bcd\uff08\u4ece\u5de6\/\u6216\u53f3\u8fb9\u6570\uff09\u7684\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>mysql&gt; select left('mysql',2),right('mysql',3);\n+-----------------+------------------+\n| left('mysql',2) | right('mysql',3) |\n+-----------------+------------------+\n| my              | sql              |\n+-----------------+------------------+\n1 row in set (0.00 sec)<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">2\u3001\u622a\u53d6\u6307\u5b9a\u4f4d\u7f6e\u548c\u957f\u5ea6\u7684\u5b57\u7b26\u4e32<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>substring(str,num,len);<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>mid(str,num,len);<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd4\u56de\u5b57\u7b26\u4e32str\u4e2d\u7684\u7b2cnum\u4e2a\u4f4d\u7f6e\u5f00\u59cb\u957f\u5ea6\u4e3alen\u7684\u5b50\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><p>mysql> select substring('zhaojd',2,3);\n+-------------------------+\n| substring('zhaojd',2,3) |\n+-------------------------+\n| hao |\n+-------------------------+\n1 row in set (0.00 sec)<\/p><p>mysql> select mid('zhapjd',2,3);\n+-------------------+\n| mid('zhapjd',2,3) |\n+-------------------+\n| hap |\n+-------------------+\n1 row in set (0.00 sec)<\/p><p>mysql> select substring('zhaojd',2,3),mid('zhaojd',2,3);\n+-------------------------+-------------------+\n| substring('zhaojd',2,3) | mid('zhaojd',2,3) |\n+-------------------------+-------------------+\n| hao | hao |\n+-------------------------+-------------------+\n1 row in set (0.00 sec)<\/p><\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">3\u3001\u66ff\u6362\u5b57\u7b26\u4e32<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>replace(str,substr,newstr);<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5c06\u5b57\u7b26\u4e32str\u4e2d\u7684\u5b50\u5b57\u7b26\u4e32substr\u7528\u5b57\u7b26\u4e32newstr\u6765\u66ff\u6362\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><code>mysql> select replace('\u8fd9\u662fMySQL\u6570\u636e\u5e93','MySQL','db2');\n+-----------------------------------------------+\n| replace('\u8fd9\u662fMySQL\u6570\u636e\u5e93','MySQL','db2') |\n+-----------------------------------------------+\n| \u8fd9\u662fdb2\u6570\u636e\u5e93 |\n+-----------------------------------------------+\n1 row in set (0.00 sec)<\/code><\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>1\u3001\u4ece\u5de6\u8fb9\u6216\u53f3\u8fb9\u622a\u53d6\u5b50\u5b57\u7b26\u4e32 left(str,num); right(str,num); \u8fd4\u56de\u5b57\u7b26\u4e32str\u4e2d&hellip; <\/p>\n<p><a class=\"moretag\" href=\"https:\/\/jiachen.de.cool\/blog\/2023\/07\/21\/%e5%ad%97%e7%ac%a6%e4%b8%b2%e6%88%aa%e5%8f%96%e4%b8%8e%e6%9b%bf%e6%8d%a2%e5%87%bd%e6%95%b0\/\">Read the full article<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[20,28,29],"class_list":["post-128","post","type-post","status-publish","format-standard","hentry","category-mysql","tag-20","tag-28","tag-29"],"_links":{"self":[{"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/posts\/128","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/comments?post=128"}],"version-history":[{"count":3,"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/posts\/128\/revisions"}],"predecessor-version":[{"id":131,"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/posts\/128\/revisions\/131"}],"wp:attachment":[{"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/media?parent=128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/categories?post=128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jiachen.de.cool\/blog\/wp-json\/wp\/v2\/tags?post=128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}