package main
    
    import (
        "errors"
        "fmt"
        "net/url"
    
        rqp "github.com/timsolov/rest-query-parser"
    )
    
    func main() {
        url, _ := url.Parse("http://localhost/?sort=name,-id&limit=10&id=1&i[eq]=5&s[eq]=one&email[like]=*tim*|name[like]=*tim*")
        q, _ := rqp.NewParse(url.Query(), rqp.Validations{
            "limit:required": rqp.MinMax(10, 100),  // limit must present in the Query part and must be between 10 and 100 (default: Min(1))
            "sort":           rqp.In("id", "name"), // sort could be or not in the query but if it is present it must be equal to "in" or "name"
            "s":      rqp.In("one", "two"), // filter: s - string and equal
            "id:int": nil,                  // filter: id is integer without additional validation
            "i:int": func(value interface{}) error { // filter: custom func for validating
                if value.(int) > 1 && value.(int) < 10 {
                    return nil
                }
                return errors.New("i: must be greater then 1 and lower then 10")
            },
            "email": nil,
            "name":  nil,
        })

        fmt.Println(q.SQL("table")) // SELECT * FROM table WHERE id = ? AND i = ? AND s = ? AND (email LIKE ? OR name LIKE ?) ORDER BY name, id DESC LIMIT 10
        fmt.Println(q.Where())      // id = ? AND i = ? AND s = ? AND (email LIKE ? OR name LIKE ?)
        fmt.Println(q.Args())       // [1 5 one %tim% %tim%]

        q.AddValidation("fields", rqp.In("id", "name"))
        q.SetUrlString("http://localhost/?fields=id,name&limit=10")
        q.Parse()

        fmt.Println(q.SQL("table")) // SELECT id, name FROM table ORDER BY id LIMIT 10
        fmt.Println(q.Select())     // id, name
        fmt.Println(q.Args())       // []
    }

    import (
        "fmt"
        "net/url"
        validation "github.com/go-ozzo/ozzo-validation/v4"
    )

    func main() {
        url, _ := url.Parse("http://localhost/?create_at[eq]=2020-10-02")
        q, _ := rqp.NewParse(url.Query(), rqp.Validations{
            "created_at": func(v interface{}) error {
                s, ok := v.(string)
                if !ok {
                    return rqp.ErrBadFormat
                }
                return validation.Validate(s, validation.Date("2006-01-02"))
            },
        })

        q.ReplaceNames(rqp.Replacer{"created_at": "DATE(created_at)"})

        fmt.Println(q.SQL("table")) // SELECT * FROM table WHERE DATE(created_at) = ?
    }