Substring search on JSON data (ERROR: cannot extract element from a scalar)

Question

我一直在寻找 this tutorial and this example 试图找到一种通过子字符串查询 JSON (<9.5)/JSONB (*9.5) 数据的高效方法。

例如，我有这个数据：

CREATE TABLE public.foo
(
  row_id SERIAL PRIMARY KEY,
  data json
);

INSERT INTO foo VALUES (1,
  '{ "name": "Book the First", "author": "Bob", "text_entry": "White Cow Walked Over the Moon" } ');
INSERT INTO foo VALUES (2,
  '{ "name": "Book the Second", "author": "Charles", "text_entry": "Humptey Dumptey sat on the Moon" } ');
INSERT INTO foo VALUES (3,
  '{ "name": "Book the Third", "author": "Jim", "text_entry": "Red Fox jumped over Brown Dog" } ');

我正在寻找一种方法来仅搜索 "text_entry" 和 return 任何具有子字符串 "the Moon" 的情况（在这种情况下，它将是 id = 1 & 2).预计 Return：

text_entry
"White Cow Walked Over the Moon" ## has the substring "the Moon"
"Humptey Dumptey sat on the Moon" ## has the substring "the Moon"

到目前为止，我的查询如下所示：

    SELECT data->'text_entry'->'%the Moon%' AS query FROM foo;

ERROR:  cannot extract element from a scalar
********** Error **********

有什么优雅的方法可以查询 JSON/B 中的子字符串吗？

Answer 1

I'm looking for a way to search ONLY "text_entry" and return any case that has the sub-string "the Moon"

SELECT data->>'text_entry' as query
FROM foo
WHERE data->>'text_entry' LIKE '%the Moon%';

->

query              
---------------------------------
White Cow Walked Over the Moon
Humptey Dumptey sat on the Moon
(2 rows)

Substring search on JSON data (ERROR: cannot extract element from a scalar)

Substring search on JSON data (ERROR: cannot extract element from a scalar)

regex

postgresql

json

jsonb