dongshu4755 2017-07-03 17:20
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扫描错误:不支持的扫描,存储驱动程序。将值类型<nil>转换为* string类型

When I try to fetch Articles without photo from mysql database:

func ArticlesAllText() ([]Article, error) {
    var err error
    var result []Article
    err = database.SQL.Select(&result, "SELECT * FROM Article WHERE photo IS NULL")
    if err != nil {
        log.Println(err)
    }
    return result, standardizeError(err)
}

I get

sql: Scan error on column index 10: unsupported Scan, storing driver.Value type into type *string

When the field value is NULL.

How can I fix this?

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1条回答 默认 最新

  • doumianfeng5065 2017-07-03 17:32
    关注

    Use sql.NullString.

    https://godoc.org/database/sql#NullString

    Personally, I hate this solution, which is why I normalize my DB so that there are no NULLs.

    Either change

    var result []Article
    

    To

    var result []sql.NullString
    

    Then take those results and make a []Article using the checks from the documentation.

    Or in your struct, change

    Photo *string
    

    To

    Photo sql.NullString
    

    And deal with the annoyance of it being a struct instead of a *string

    Thanks to ATN, see here for a guide https://medium.com/aubergine-solutions/how-i-handled-null-possible-values-from-database-rows-in-golang-521fb0ee267

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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