我在Oracle 12c上运行以下代码：
DECLARE
l_json clob;
l_var varchar2(90);
l_query clob;
mypath clob;
l_path_value varchar2(100);
BEGIN
SELECT json_column into l_json from my_table;
SELECT path_column into l_path_value from my_table; -- this returns 'watchers'
mypath := '$.second."'||l_path_value||'"'; -- $.second."watchers"
l_query := 'select json_value('''||l_json||''', '''||mypath||''' ERROR ON ERROR) from dual';
execute Immediate l_query into l_var;
DBMS_OUTPUT.PUT_LINE('var: '||l_var);
END;
运行之后，我得到的结果如下：
错误报告 -
ORA-40441：JSON语法错误
ORA-06512：第12行 40441. 00000 - ＆＃34; JSON语法错误＆＃34;
*原因：提供的JavaScript Object Notation（JSON）数据无效 语法，无法解析 *操作：使用正确的语法提供JSON数据。
我期待结果如下：
var：0
那么JSON的长度是否存在问题？
我的json看起来像：
{
"first": {
"private": false,
"html_url": "https://github.com/mralexgray/Alfred-Google-Translate",
"description": "Extension for Alfred that will do a Google translate for you",
"fork": true,
"url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate",
"forks_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/forks",
"keys_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/keys{/key_id}",
"collaborators_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/collaborators{/collaborator}",
"teams_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/teams",
"hooks_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/hooks",
"issue_events_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/issues/events{/number}",
"events_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/events",
"assignees_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/assignees{/user}",
"branches_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/branches{/branch}",
"tags_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/tags",
"blobs_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/blobs{/sha}",
"git_tags_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/tags{/sha}",
"git_refs_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/refs{/sha}",
"trees_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/trees{/sha}",
"statuses_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/statuses/{sha}",
"languages_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/languages",
"stargazers_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/stargazers",
"contributors_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/contributors",
"subscribers_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/subscribers",
"subscription_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/subscription",
"commits_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/commits{/sha}",
"git_commits_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/commits{/sha}",
"comments_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/comments{/number}",
"issue_comment_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/issues/comments{/number}",
"contents_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/contents/{+path}",
"compare_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/compare/{base}...{head}",
"merges_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/merges",
"archive_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/{archive_format}{/ref}",
"downloads_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/downloads",
"issues_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/issues{/number}",
"pulls_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/pulls{/number}",
"milestones_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/milestones{/number}",
"notifications_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/notifications{?since,all,participating}",
"labels_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/labels{/name}",
"releases_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/releases{/id}",
"deployments_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/deployments",
"created_at": "2013-06-04T10:45:10Z",
"updated_at": "2013-06-04T10:45:10Z",
"pushed_at": "2013-01-12T19:39:03Z",
"git_url": "git://github.com/mralexgray/Alfred-Google-Translate.git",
"ssh_url": "git@github.com:mralexgray/Alfred-Google-Translate.git",
"clone_url": "https://github.com/mralexgray/Alfred-Google-Translate.git",
"svn_url": "https://github.com/mralexgray/Alfred-Google-Translate",
"homepage": null,
"size": 103,
"stargazers_count": 0,
"watchers_count": 0,
"language": "Shell",
"has_issues": false,
"has_downloads": true,
"has_wiki": true,
"has_pages": false,
"forks_count": 0,
"mirror_url": null,
"open_issues_count": 0,
"forks": 0,
"open_issues": 0,
"watchers": 0,
"default_branch": "master"
},
"second": {
"private": false,
"html_url": "https://github.com/mralexgray/Alfred-Google-Translate",
"description": "Extension for Alfred that will do a Google translate for you",
"fork": true,
"url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate",
"forks_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/forks",
"keys_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/keys{/key_id}",
"collaborators_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/collaborators{/collaborator}",
"teams_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/teams",
"hooks_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/hooks",
"issue_events_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/issues/events{/number}",
"events_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/events",
"assignees_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/assignees{/user}",
"branches_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/branches{/branch}",
"tags_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/tags",
"blobs_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/blobs{/sha}",
"git_tags_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/tags{/sha}",
"git_refs_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/refs{/sha}",
"trees_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/trees{/sha}",
"statuses_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/statuses/{sha}",
"languages_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/languages",
"stargazers_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/stargazers",
"contributors_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/contributors",
"subscribers_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/subscribers",
"subscription_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/subscription",
"commits_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/commits{/sha}",
"git_commits_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/git/commits{/sha}",
"comments_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/comments{/number}",
"issue_comment_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/issues/comments{/number}",
"contents_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/contents/{+path}",
"compare_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/compare/{base}...{head}",
"merges_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/merges",
"archive_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/{archive_format}{/ref}",
"downloads_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/downloads",
"issues_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/issues{/number}",
"pulls_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/pulls{/number}",
"milestones_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/milestones{/number}",
"notifications_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/notifications{?since,all,participating}",
"labels_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/labels{/name}",
"releases_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/releases{/id}",
"deployments_url": "https://api.github.com/repos/mralexgray/Alfred-Google-Translate/deployments",
"created_at": "2013-06-04T10:45:10Z",
"updated_at": "2013-06-04T10:45:10Z",
"pushed_at": "2013-01-12T19:39:03Z",
"git_url": "git://github.com/mralexgray/Alfred-Google-Translate.git",
"ssh_url": "git@github.com:mralexgray/Alfred-Google-Translate.git",
"clone_url": "https://github.com/mralexgray/Alfred-Google-Translate.git",
"svn_url": "https://github.com/mralexgray/Alfred-Google-Translate",
"homepage": null,
"size": 103,
"stargazers_count": 0,
"watchers_count": 0,
"language": "Shell",
"has_issues": false,
"has_downloads": true,
"has_wiki": true,
"has_pages": false,
"forks_count": 0,
"mirror_url": null,
"open_issues_count": 0,
"forks": 0,
"open_issues": 0,
"watchers": 0,
"default_branch": "master"
}
}
答案 0 :(得分：0)
如果你的varchar2（90）对于返回值来说太小，它可能会返回null。请参阅JSON_value_on_error_clause以获取参考。
答案 1 :(得分：0)
我不确定它会有所帮助 - 您已经证明它没有任何区别的示例，我不确定是否有任何控件或多字节字符在不同的值可能会导致问题 - 但我会绑定JSON值，而不是隐式转换为字符串并返回：
l_query := 'select json_value(:json, '''||mypath||''' ERROR ON ERROR) from dual';
execute Immediate l_query into l_var using l_json;