CODEWITHSUNDEEP
sqlpostgresql
Mateusz Urbański
Mateusz Urbański

Reputation: 7862

malformed array literal - PostgreSQL

I want to copy an array from jsonb field to a PostgreSQL array column:

CREATE TABLE survey_results (
    id integer NOT NULL,
    areas text[],  
    raw jsonb DEFAULT '{}'::jsonb
);

INSERT INTO survey_results (id, raw)
    VALUES (1, '{"areas": ["test", "test2"]}');

UPDATE survey_results SET areas = CAST(raw#>>'{areas}' AS text[]);

This returns me?

ERROR: malformed array literal: "["test", "test2"]" Detail: "[" must introduce explicitly-specified array dimensions.

How can I fix that?

http://sqlfiddle.com/#!17/d8122/2

Upvotes: 25

Views: 127702

Answers (2)

Gesugao-san
Gesugao-san

Reputation: 75

For Node.JS, this task could be solved approximately as follows:

// const { Client } = require('discord.js');
let user_input = 123; // for example
let fetchedInvite = await client.fetchInvite(user_input);
const features = fetchedInvite.guild.features;
// ['BANNER', /*.../* 'PREVIEW_ENABLED'];
const featuresPreparedToQuery = JSON.stringify(features)
    .replace('[', '{')
    .replace(']', '}');
console.log("featuresPreparedToQuery:", featuresPreparedToQuery);
// {'BANNER', /*.../* 'PREVIEW_ENABLED'}

Upvotes: 0

Vao Tsun
Vao Tsun

Reputation: 51466

http://sqlfiddle.com/#!17/d8122/33

json array is not self castable to postgres array. You need to either properly parse and cast it (json_array_elements, unnest, array_agg), or use some monkey hack, like:

UPDATE survey_results 
SET areas = concat('{',translate(raw#>>'{areas}','"',$$'$$),'}')::text[];

above I "prepare" json array, by changing quotes, so they would be literal, not identifier ones and prepare it to postgres array text representation '{}'

as alternative smth like:

with a as (
  select jsonb_array_elements_text(raw#>'{areas}') e from survey_results 
)
, b as (
select array_agg(e) ag from a
)
UPDATE survey_results 
SET areas = ag::text[]
FROM b;
select * from survey_results
  ;

can be used - for safer "casting"

Upvotes: 16

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