You can use the JSONEachRow
function in ClickHouse to convert a JSON array into rows. This function takes a string or a JSON object as input and returns a table with one row for each element in the array. Here's an example:
Assume you have the following JSON string:
'["apple", "orange", "banana"]'
To convert this JSON array into rows in ClickHouse, you can use the JSONEachRow
function in a query:
SELECT * FROM JSONEachRow('["apple", "orange", "banana"]')
This will return a table with one row for each element in the array:
┌─key─┬─value─┐
│ 1 │ apple │
│ 2 │ orange│
│ 3 │ banana│
└─────┴───────┘
You can also use this function directly on a column containing JSON arrays. For example, if you have a table fruits
with a column names
containing JSON arrays of fruit names:
┌────┬─────────────────────┐
│ id │ names │
├────┼─────────────────────┤
│ 1 │ ["apple", "orange"] │
│ 2 │ ["banana", "kiwi"] │
└────┴─────────────────────┘
You can use JSONEachRow
to expand the arrays into rows:
SELECT id, value FROM fruits
ARRAY JOIN JSONEachRow(names) AS value
┌─id─┬─value─┐
│ 1 │ apple │
│ 1 │ orange│
│ 2 │ banana│
│ 2 │ kiwi │
└────┴───────┘
This will return a table with one row for each array element, with the original id
value and the expanded value
column.
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Asked: 2022-12-05 11:00:00 +0000
Seen: 16 times
Last updated: Apr 20 '22
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