{"id":26202,"date":"2018-06-29T23:59:30","date_gmt":"2018-06-29T15:59:30","guid":{"rendered":"http:\/\/www.fagao.me\/?p=26202"},"modified":"2018-06-29T23:59:30","modified_gmt":"2018-06-29T15:59:30","slug":"sql%e8%af%ad%e5%8f%a5%e6%8a%80%e5%b7%a7%e5%ad%a6%e4%b9%a0%e7%b3%bb%e5%88%97%e4%b9%8b%e6%9f%a5%e8%af%a2%e5%b7%a5%e8%b5%84%e6%8e%92%e5%90%8d%e7%ac%ac%e4%ba%8c%e7%9a%84%e5%91%98%e5%b7%a5%e5%b7%a5","status":"publish","type":"post","link":"https:\/\/www.fagao.me\/p\/26202.htm","title":{"rendered":"SQL\u8bed\u53e5\u6280\u5de7\u5b66\u4e60\u7cfb\u5217\u4e4b\u67e5\u8be2\u5de5\u8d44\u6392\u540d\u7b2c\u4e8c\u7684\u5458\u5de5\u5de5\u8d44"},"content":{"rendered":"

\"\"<\/p>\n

\u9700\u6ce8\uff1a\u7f16\u5199SQL\u67e5\u8be2\u51fa\u5458\u5de5\u8868\u4e2d\u6392\u540d\u7b2c\u4e8c\u7684\u5de5\u8d44\uff08\u4f7f\u7528MYSQL\u6570\u636e\u5e93\uff09\u3002<\/p>\n

+\u2014\u2014+ ——– +<\/p>\n

| ID |\u5de5\u8d44|<\/p>\n

+\u2014\u2014+ ——– +<\/p>\n

| 1 | 100 |<\/p>\n

| 2 | 200 |<\/p>\n

| 3 | 300 |<\/p>\n

+\u2014\u2014+ ——– +<\/p>\n

<\/div>\n

\u7f51\u7edc\u914d\u56fe<\/p>\n

\u4f8b\u5982\uff0c\u7ed9\u5b9a\u4e0a\u9762\u7684\u5458\u5de5\u8868\uff0c\u6309\u8981\u6c42\u67e5\u8be2\u5e94\u8be5\u8fd4\u56de200\u4f5c\u4e3a\u7b2c\u4e8c\u9ad8\u5de5\u8d44\uff0c\u5982\u679c\u6ca1\u6709\u7b2c\u4e8c\u9ad8\u7684\u5de5\u8d44\uff0c\u90a3\u4e48\u67e5\u8be2\u5e94\u8be5\u8fd4\u56denull\u3002<\/p>\n

——————— + +<\/p>\n

| \u7b2c\u4e8c\u9ad8\u5de5\u8d44 |<\/p>\n

——————— + +<\/p>\n

200 | |<\/p>\n

——————— + +<\/p>\n

\u89e3\u51b3\u65b9\u6cd5\u4e00\uff1a<\/p>\n

\u65b9\u6cd5\uff1a\u4f7f\u7528\u5b50\u67e5\u8be2\u548c\u9650\u5236\u5b50\u53e5\uff1b<\/p>\n

\u7b97\u6cd5\uff1a\u5c06\u8868\u4e2d\u7684\u5de5\u8d44\u6309\u964d\u5e8f\u6392\u5e8f\uff0c\u7136\u540e\u5229\u7528\u9650\u5236\u6761\u4ef6\u7b2c\u4e8c\u9ad8\u5de5\u8d44\u3002<\/p>\n

SELECT DISTINCT<\/p>\n

Salary AS SecondHighestSalary<\/p>\n

FROM<\/p>\n

Employee<\/p>\n

ORDER BY Salary DESC<\/p>\n

LIMIT 1 OFFSET 1<\/p>\n

\u7136\u800c\uff0c\u5982\u679c\u6ca1\u6709\u7b2c\u4e8c\u9ad8\u5de5\u8d44\uff0c\u8fd9\u4e2a\u89e3\u51b3\u65b9\u6cd5\u5c06\u8ba4\u4e3a\u662f\u201c\u9519\u8bef\u7684\u65b9\u6cd5\u201d\uff0c\u56e0\u4e3a\u8868\u4e2d\u53ef\u80fd\u53ea\u6709\u4e00\u6761\u8bb0\u5f55\uff0c\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u6211\u4eec\u53ef\u4ee5\u628a\u5b83\u4f5c\u4e3a\u4e34\u65f6\u8868\uff0c\u4fee\u6539\u540e\u7684\u6b63\u786e\u8bed\u53e5\u5982\u4e0b\u3002<\/p>\n

SELECT<\/p>\n

(SELECT DISTINCT<\/p>\n

Salary<\/p>\n

FROM<\/p>\n

Employee<\/p>\n

ORDER BY Salary DESC<\/p>\n

LIMIT 1 OFFSET 1) AS SecondHighestSalary<\/p>\n

;<\/p>\n

\u89e3\u51b3\u65b9\u6cd5\u4e8c\uff1a\u8fd9\u4e2a\u65b9\u6cd5\u4f7f\u7528\u6570\u636e\u5e93\u7684ifnull\u529f\u80fd\u89e3\u51b3\u201c\u7a7a\u201d\u7684\u95ee\u9898\uff0cSQL\u8bed\u53e5\u5982\u4e0b\u3002<\/p>\n

SELECT<\/p>\n

IFNULL(<\/p>\n

(SELECT DISTINCT Salary<\/p>\n

FROM Employee<\/p>\n

ORDER BY Salary DESC<\/p>\n

LIMIT 1 OFFSET 1),<\/p>\n

NULL) AS SecondHighestSalary<\/p>\n","protected":false},"excerpt":{"rendered":"

\u9700\u6ce8\uff1a\u7f16\u5199SQL\u67e5\u8be2\u51fa\u5458\u5de5\u8868\u4e2d\u6392\u540d\u7b2c\u4e8c\u7684\u5de5\u8d44\uff08\u4f7f\u7528MYSQL\u6570\u636e\u5e93\uff09\u3002 +\u2014\u2014+ —— […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[144],"class_list":["post-26202","post","type-post","status-publish","format-standard","hentry","category-news","tag-144"],"_links":{"self":[{"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/posts\/26202","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/comments?post=26202"}],"version-history":[{"count":0,"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/posts\/26202\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/media?parent=26202"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/categories?post=26202"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fagao.me\/p\/wp-json\/wp\/v2\/tags?post=26202"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}