type diffrent when Query() args is blank

[cgyy]

db.Query("select * from users where id>?", 1)
type of rows['id'] is uint8

db.Query("select * from users where id>1")
type of rows['id'] is int64

rs, _ := db.Query("select id from tasks where id> 1 limit 1")
//rs, er := db.Query("select id from tasks where id>? limit 1", 1)

for rs.Next() {

    var i1  interface{}
    rs.Scan(&i1)
    switch t := i1.(type) {
    case []uint8:
        fmt.Println("[]uint8", string(t)) //when args is blank
    case int:
        fmt.Println("int")
    case int64:
        fmt.Println("int64")  //when args is not blank
    default:
        fmt.Println("default", t)
    }

    fmt.Println(i1)
    break
}

[julienschmidt]

This is behavior is intended and allowed by the sql package specs.

If you scan into interface{} essentially you are saying that you don't care about the return type.
If the query does not include args the mysql package uses the text protocol, so it gets the result as a string representation ([]byte aka. []uint8).
If the query includes parameters, the binary protocol (prepared statements) must be used which gives a result in binary form. The mysql package reads it into a int64 then.

If you care about the return type, don't use interface{}, the sql package converts the type then.

[cgyy]

got it ,thank you!