MySQL stored procedure with variable argument list

Question

I have made a stored procedure. I want it to filter the data by different parameters. If I pass one parameter, it should be filtered by one; if I pass two, it should be filt

Answer 1

I found a JSON-based approach which works with the latest MySQL/MariaDB systems. Check the link below (Original Author is Federico Razzoli): https://federico-razzoli.com/variable-number-of-parameters-and-optional-parameters-in-mysql-mariadb-procedures

Basically, you take a BLOB parameter which is actually a JSON object and then do JSON_UNQUOTE(JSON_EXTRACT(json object, key)) as appropriate.

Lifted an extract here:

CREATE FUNCTION table_exists(params BLOB)
    RETURNS BOOL
    NOT DETERMINISTIC
    READS SQL DATA
    COMMENT '
Return whether a table exists.
Parameters must be passed in a JSON document:
* schema (optional). : Schema that could contain the table.
                       By default, the schema containing this procedure.
* table              : Name of the table to check.
'
BEGIN
    DECLARE v_table VARCHAR(64)
        DEFAULT JSON_UNQUOTE(JSON_EXTRACT(params, '$.table'));
    DECLARE v_schema VARCHAR(64)
        DEFAULT JSON_UNQUOTE(JSON_EXTRACT(params, '$.schema'));

    IF v_schema IS NULL THEN
        RETURN EXISTS (
            SELECT TABLE_NAME
                FROM information_schema.TABLES
                WHERE
                    TABLE_SCHEMA = SCHEMA()
                    AND TABLE_NAME = v_table
        );
    ELSE
        RETURN EXISTS (
            SELECT TABLE_NAME
                FROM information_schema.TABLES
                WHERE
                    TABLE_SCHEMA = v_schema
                    AND TABLE_NAME = v_table
        );
    END IF;
END;