Building a nested hierarchy of JSON in a relational DB
https://lakshminp.com/building-nested-hierarchy-json-relational-db
其中,不要coalesce
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SELECT id, name, COALESCE(get_children(id), '[]') as children from genres
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改成
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SELECT id as text, get_children(id) as nodes from genres
另外,去除JSON中null的代码:
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function removeNulls(obj){
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var isArray = obj instanceof Array;
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for (var k in obj){
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if (obj[k]===null) isArray ? obj.splice(k,1) : delete obj[k];
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else if (typeof obj[k]=="object") removeNulls(obj[k]);
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}
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}
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removeNulls(root);
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return JSON.stringify(root,null,2);
来自 “ ITPUB博客 ” ,链接:https://blog.itpub.net/9697/viewspace-2142727/
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