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DBRecordTable._ID is a INTEGER + PRIMARY_KEY+ AUTOINCREMENT, I hope to get the max _id value of a table, zero will be return if no data row in the table.

I try to write the code select(tableName,DBRecordTable._ID).orderBy(DBRecordTable._ID, Desc).limit(1), but it's not correct, how can I fix it?

Code

class DBRecordHandler(private val mDBHelper: DBRecordHelper =DBRecordHelper.instance,

                      private val tableName:String =DBRecordTable.TableNAME,

                      private val idField:String=DBRecordTable._ID

                      ) {



 fun getMaxID():Long=mDBHelper.use{

      var myList=select(tableName,DBRecordTable._ID).orderBy(DBRecordTable._ID, Desc).limit(1); 

 }



}







class DBRecordHelper(mContext: Context = UIApp.instance) : ManagedSQLiteOpenHelper(mContext, DB_NAME, null, DB_VERSION) {



    companion object {

        const val DB_NAME = "record.db"

        const val DB_VERSION = 5

        val instance by lazy { DBRecordHelper() }

    }



    override fun onCreate(db: SQLiteDatabase) {

        db.createTable( DBRecordTable.TableNAME , true,

            DBRecordTable._ID to INTEGER + PRIMARY_KEY+ AUTOINCREMENT,           

            DBRecordTable.CreatedDate to INTEGER

        )

    }   



}

You can find maximum id of the table contents using SQL MAX() function:

private fun getMaxID(): Int {

    var maxId = 0

    mDBHelper?.use {

        select(DBRecordTable.TableNAME, "MAX(${DBRecordTable._ID}) as maxId").exec {

            moveToNext()

            maxId = getInt(getColumnIndex("maxId"))

        }

    }

    return maxId

}