// GetMaxId returns max id of a specified table.
func GetMaxId(tableName dna.String, db *sqlpg.DB) (dna.Int, error) {
var maxid dna.Int
err := db.QueryRow("SELECT max(id) FROM " + tableName).Scan(&maxid)
switch {
case err == sqlpg.ErrNoRows:
return 0, err
case err != nil:
return 0, err
default:
return maxid, nil
}
}
// SelectLastMissingIds returns a list of ids which is missing from a table.
// nLastIds is the total number of last ids in the table.
//
// Example: 3 last ids from table nssongs are 1,4,5. Therefore, the missing
// ids whose range is from 1->5 are 2,3.
func SelectLastMissingIds(tblName dna.String, nLastIds dna.Int, db *sqlpg.DB) (*dna.IntArray, error) {
var min, max dna.Int
query := dna.Sprintf("SELECT min(id), max(id) FROM (SELECT id FROM %v ORDER BY id DESC LIMIT %v) as AB", tblName, nLastIds)
// dna.Log(query)
db.QueryRow(query).Scan(&min, &max)
// totalItem := max - min + 1
// var ids = make(dna.IntArray, totalItem, totalItem+100)
// var idx = 0
// for i := min; i < max; i++ {
// ids[idx] = i
// idx += 1
// }
return SelectMissingIdsWithRange(tblName, min, max, db)
}