{"id":208334,"date":"2025-07-08T09:06:31","date_gmt":"2025-07-08T01:06:31","guid":{"rendered":"https:\/\/server.hk\/cnblog\/208334\/"},"modified":"2025-07-08T09:06:31","modified_gmt":"2025-07-08T01:06:31","slug":"%e5%a6%82%e4%bd%95%e8%8e%b7%e5%8f%96%e9%80%89%e6%8b%a91%e6%95%b0%e6%8d%ae","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/208334\/","title":{"rendered":"\u5982\u4f55\u83b7\u53d6\u201c\u9009\u62e91\u201d\u6570\u636e"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> \u5982\u4f55\u83b7\u53d6\u201c\u9009\u62e91\u201d\u6570\u636e<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-05-01 21:54:36<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u5b66\u4e60\u77e5\u8bc6\u8981\u5584\u4e8e\u601d\u8003\uff0c\u601d\u8003\uff0c\u518d\u601d\u8003\uff01\u4eca\u5929\u5c0f\u7f16\u5c31\u7ed9\u5927\u5bb6\u5e26\u6765\u300a\u5982\u4f55\u83b7\u53d6\u201c\u9009\u62e91\u201d\u6570\u636e\u300b<\/span>\uff0c\u4ee5\u4e0b\u5185\u5bb9\u4e3b\u8981\u5305\u542b<\/span>\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u4f60\u6b63\u5728\u5b66\u4e60\u6216\u51c6\u5907\u5b66\u4e60Golang<\/span>\uff0c\u5c31\u90fd\u4e0d\u8981\u9519\u8fc7\u672c\u6587\u5566~\u8ba9\u6211\u4eec\u4e00\u8d77\u6765\u770b\u770b\u5427\uff0c\u80fd\u5e2e\u52a9\u5230\u4f60\u5c31\u66f4\u597d\u4e86\uff01<\/span><\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

\u6211\u8bd5\u56fe\u786e\u5b9a\u6570\u636e\u5e93\u4e2d\u662f\u5426\u5b58\u5728\u67d0\u4e2a\u503c\uff0c\u56e0\u6b64\u6211\u9009\u62e9\u4f7f\u7528 select 1 from table<\/code>\uff0c\u4f46\u662f\u5982\u4f55\u83b7\u53d6\u6570\u636e\uff1f \u6211\u60f3\u68c0\u67e5\u4e24\u4e2a\u4eba\u662f\u5426\u662f\u597d\u53cb\uff0c\u8fd9\u662f\u6211\u7684\u6a21\u578b<\/p>\n

type buddy struct {\n    id      uint64 `gorm:\"primarykey\"`\n    userid  uint32\n    buddyid uint32\n}\n<\/pre>\n
\u8fd9\u662f\u6211\u5c1d\u8bd5\u8fc7\u7684gorm sql<\/p>\n
\/\/ select 1 from buddies where user_id=? and buddy_id=?\ntype Result struct {\n    Exist uint32\n}\nexist := &Result{}\norm.DB.Debug().Table(\"buddies\").Raw(\"SELECT 1 as exist FROM buddies WHERE user_id = ? and buddy_id = ?\", userID, buddyID).Scan(exist)\n<\/pre>\n
\u4f46\u662f\u6211\u6ca1\u6709\u5728exist.exist\u4e2d\u5f97\u5230\u4efb\u4f55\u4e1c\u897f<\/p>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
\u8fd9\u91cc\u6709\u4e00\u4e2a\u51fd\u6570\u53ef\u4ee5\u6309\u7167\u60a8\u7684\u8981\u6c42\u5e76\u4ee5\u6700\u4f73\u65b9\u5f0f\u6267\u884c<\/p>\n
package main\n    \n    import (\n        \"gorm.io\/driver\/sqlite\"\n        \"gorm.io\/gorm\"\n        \"log\"\n    )\n    \n    type buddy struct {\n        id      uint64 `gorm:\"primarykey\"`\n        userid  uint32\n        buddyid uint32\n    }\n    func main() {\n        db, err := gorm.open(sqlite.open(\"test.db\"), &gorm.config{})\n        if err != nil {\n            panic(\"failed to connect database\")\n        }\n    \n        \/\/ migrate the schema\n        db.automigrate(&buddy{})\n    \n        \/\/ create\n        db.create(&buddy{userid: 1, buddyid: 2})\n        db.create(&buddy{userid: 2, buddyid: 1})\n        db.create(&buddy{userid: 3, buddyid: 1})\n    \n        var exists bool\n        db.raw(\"select case count(1) when 0 then false else true end from buddies where user_id = ? and buddy_id = ?\", 1, 2).scan(&exists)\n        log.print(exists)\n        db.raw(\"select case count(1) when 0 then false else true end from buddies where user_id = ? and buddy_id = ?\", 3, 2).scan(&exists)\n        log.print(exists)\n    }<\/pre>\n
\u60a8\u53ef\u4ee5\u68c0\u67e5\u5b83\u662f\u5426\u6709\u6548<\/p>\n
queryResult := db.Where(fmt.Sprintf(\"user_id = %d and buddy_id = %d\", 1, 2).Find(&Buddy)\n    if queryResult.Error == nil {\n       \/\/you can also check queryResult.RowsAffected > 0\n        result = queryResult.Statement.Model \/\/get the returned data\n    } else {\n        \/\/do something with queryResult.Error\n    }<\/pre>\n
\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300a\u5982\u4f55\u83b7\u53d6\u201c\u9009\u62e91\u201d\u6570\u636e\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u516c\u4f17\u53f7\u5427\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-208334","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208334","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=208334"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208334\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=208334"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=208334"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=208334"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}