sqlarraysh2

SELECT FROM H2 text array using LIKE wildcard


I have an H2 column with type TEXT ARRAY.

CREATE TABLE app.worklist
(
    id INT,
    profession TEXT ARRAY
);

I would like to query if any array element matches a LIKE parameter.

The following works in Postgres:

SELECT * FROM app.worklist
 WHERE EXISTS (
    SELECT
    FROM unnest(profession) AS p
    WHERE p LIKE 'A%'
);

However, it fails in H2 org.h2.jdbc.JdbcSQLSyntaxErrorException: Column "PROFESSION" not found; due to a long unfixed bug.

How can I accomplish this in H2?


Solution

  • After days of research, I determined that it is not possible to do this cleanly in H2.

    Our team used a workaround. When the data is ingested, we flatten the array.

    CREATE TABLE app.worklist
    (
        id INT,
        profession VARCHAR(65536)
    );
    

    We joined each element with control character 0x1a. ["foo", "bar"] becomes "{0x1a}foo{0x1a}bar{0x1a}"

    val profession = professionArray.joinToString(
       separator = "\u001A",
       prefix = "\u001A",
       postfix = "\u001A",
    )
    

    To search, we execute:

    SELECT *
       FROM app.worklist
       WHERE profession LIKE '{0x1a}A%';
    

    This solution only works if

    1. you know the length of your data.
    2. you know the the control character won't be present in the original text array.
    3. you are looking for 'A%', '%A', or '%A%'; it doesn't work for combined expressions like 'A%B'.