使用gorm golang在多个表中进行动态列搜索

Question

My scenario is i have a grid with search option where user can select the column and can do the search, the grid data is coming from various tables. I have attached a sample screen of grid.

User Screen

So i'm trying to create a dynamic query for search but the problem is i can able to search only in main table (schema.Robot) not in Preload tables. whenever i trying to search data data from Preload tables let say from RobotModel table that time getting below error

pq: missing FROM-clause entry for table "robot_models"

Here is my go code

func (r *RobotsRepository) GetRobotsSummary(listParams viewmodel.ListParams, companyID uint) ([]*schema.Robot, int, error) {
mrobots := []*schema.Robot{}
var count int
var order string
if listParams.SortColumn == "" {
    listParams.SortColumn = "id"
    listParams.SortOrder = 1
} else {
    listParams.SortColumn = util.Underscore(listParams.SortColumn)
}
if listParams.SortOrder == 0 {
    order = "ASC"
} else {
    order = "DESC"
}

var searchQuery string
if listParams.SearchText != "" {
    switch listParams.SearchColumn {
    case "Robot":
        listParams.SearchColumn = "name"
    case "Model":
        listParams.SearchColumn = "robot_models.name"
    }
    searchQuery = listParams.SearchColumn +" LIKE '%"+ listParams.SearchText +"%' and Company_ID = " + fmt.Sprint(companyID)
}else{
    searchQuery = "Company_ID = " + fmt.Sprint(companyID)
}   

orderBy := fmt.Sprintf("%s %s", listParams.SortColumn, order)

err := r.Conn.
    Preload("RobotModel", func(db *gorm.DB) *gorm.DB {
        return db.Select("ID,Name")
    }).
    Preload("Task", func(db *gorm.DB) *gorm.DB {
        return db.Where("Task_Status in ('In-Progress','Pending')").Select("ID, Task_Status")
    }).
    Preload("CreatedUser", func(db *gorm.DB) *gorm.DB {
        return db.Select("ID,Display_Name")
    }).
    Preload("UpdatedUser", func(db *gorm.DB) *gorm.DB {
        return db.Select("ID,Display_Name")
    }).
    Where(searchQuery).
    Order(orderBy).
    Offset(listParams.PageSize * (listParams.PageNo - 1)).
    Limit(listParams.PageSize).
    Find(&mrobots).Error

r.Conn.Model(&schema.Robot{}).Where(searchQuery).Count(&count)

return mrobots, count, err 
}

In searchQuery variable i'm storing my dynamic query. My question is how can i search data for preload table columns

Here is the sql query which i'm trying to achieve using gorm

SELECT robots.id,robots.name,robot_models.name as 
model_name,count(tasks.task_status) as task_on_hand,
robots.updated_at,users.user_name as updated_by
FROM rfm.robots as robots
left join rfm.tasks as tasks on tasks.robot_id = robots.id and 
tasks.task_status in ('In-Progress','Pending') 
left join rfm.robot_models as robot_models on robot_models.id = 
robots.robot_model_id 
left join rfm.users as users on users.id = robots.updated_by 
WHERE robot_models.name::varchar like '%RNR%' and robots.deleted_at is null 
GROUP BY robots.id,robot_models.name,users.user_name 
ORDER BY task_on_hand DESC LIMIT 2 OFFSET 0

and sorry for bad English!

Answer 1

Even though you are preloading, you are still required to explicitly use joins when filtering and ordering on columns on other tables. Preloading is used to eagerly load the data to map into your models, not to join tables.

Chain on something like this:

.Joins("LEFT JOIN rfm.robot_models AS robot_models ON robot_models.id = robots.robot_model_id")

I'm not positive if you can use the AS keyword using this technique, but if not, it should be easy enough to adjust your query accordingly.