Go MySQL queries with SET variables

Question

I'm trying to clean up how Go is calling MySQL queries by setting some variables before running the query with a decent amount of case statements around a single value. The query I'm attempting to run works fine on the console but is failing on me with a syntax issue at the SELECT when running it through Go. Is something like this possible?

func (d *DB) SelectByUserId(uid string, srt string, pg, lim int) ([]Inventory, error) {
    query := `
    SET @user_id := ?,
        @orderBy := ?;
    SELECT
        *
    FROM
        inventory
    WHERE
        user_id = @user_id
    ORDER BY
        (CASE WHEN @orderBy = 'type,asc' THEN type END),
        (CASE WHEN @orderBy = 'type,desc' THEN type END) DESC,
        (CASE WHEN @orderBy = 'visible,asc' THEN visible END),
        (CASE WHEN @orderBy = 'visible,desc' THEN visible END) DESC,
        (CASE WHEN @orderBy = 'create_date,asc' THEN create_date END),
        (CASE WHEN @orderBy = 'create_date,desc' THEN create_date END) DESC,
        (CASE WHEN @orderBy = 'update_date,asc' THEN update_date END),
        (CASE WHEN @orderBy = 'update_date,desc' THEN update_date END) DESC
    LIMIT ?,?;
    `
    
    rows, err := d.Query(
        query,
        uid,
        srt,
        pg*lim,
        lim,
    )

    if err != nil {
        return nil, err
    }
    defer rows.Close()

    result := make([]Inventory, 0)
    for rows.Next() {
        var inv Inventory
        if err := rows.Scan(
            &inv.Id,
            &inv.UserId,
            &inv.Type,
            &inv.Name,
            &inv.Description,
            &inv.Visible,
            &inv.CreateDate,
            &inv.UpdateDate); err != nil {
            return result, err
        }
        result = append(result, inv)
    }
    if err = rows.Err(); err != nil {
        return result, err
    }

    return result, nil
}

Now, if I take out the SET pieces and replace all the @ variables with the ? and then pass the srt variable in multiple times like below this all works. But would really like to not have to have a query call such as:

rows, err := d.Query(
        query,
        uid,
        srt,
        srt,
        srt,
        srt,
        srt,
        srt,
        srt,
        srt,
        pg*lim,
        lim)

The error being reported isn't very helpful:

Error 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT\n    *\nFROM\n    inventory\nWHERE\n    user_id = @user_id\nORDER BY\n ' at line 3

Thanks for your help.

Answer 1

For those interested I've solved my issue with a few updates.

1. There are settings on the DSN when connecting ?...&multiStatements=true&interpolateParams=true

2. After adding the above I started getting a new error regarding the collation (Illegal mix of collations (utf8mb4_0900_ai_ci,IMPLICIT) and (utf8mb4_general_ci,IMPLICIT) for operation '='. I went through and converted the DB and the tables to utf8mb4_general_ci and everything is working as expected.

Thank you to those that provided their solutions but this is the route we wound up taking.