Question

我的jsonb表中有一个名为chores的{{1}}列，其数据看起来像这样：

work

每个用户在[{"task": "feed_dog", "value": "Daily"},{"task": "mop_floor", "value": "Weekly"]数组中可能有零到几十个任务。

如何按任务名称查询？例如，拉出至少一个chores为task的所有记录。

feed_dog和SELECT chores->>'task' FROM work一样返回一堆null结果。

Answer 1

您需要取消嵌套数组：

/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-scenegraph/src/util/bound.js:18
  return g2D || (g2D = canvas.instance(1,1).getContext('2d'));
                                           ^

TypeError: Cannot read property 'getContext' of null
    at context (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-scenegraph/src/util/bound.js:18:44)
    at textMark (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-scenegraph/src/util/bound.js:169:11)
    at Object.itemBounds [as item] (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-scenegraph/src/util/bound.js:259:3)
    at /Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega/src/scene/Bounder.js:36:13
    at Array.forEach (<anonymous>)
    at Bounder.proto.evaluate (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega/src/scene/Bounder.js:35:15)
    at Model.prototype.evaluate (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-dataflow/src/Graph.js:329:16)
    at Builder.proto.evaluate (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega/src/scene/Builder.js:227:26)
    at Model.prototype.evaluate (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-dataflow/src/Graph.js:329:16)
    at Model.prototype.propagate (/Users/sambarnett/.webppl/node_modules/webppl-viz/node_modules/vega-dataflow/src/Graph.js:161:22)

使用Postgres 12可以更容易地编写它：

select w.*
from "work" w
where exists (select *
              from jsonb_array_elements(w.chores) as t(task)
              where t.task ->> 'task" = 'feed_dog');

查询jsonb列中的数组值

1 个答案: