You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: auniqueindex.xo.go
    path of file: ./repos/xo/_examples/a_bit_of_everything/oracle
    
    the code of the file until where you have to start completion: package oracle

// Code generated by xo. DO NOT EDIT.

import (
	"context"
	"database/sql"
)

// AUniqueIndex represents a row from 'a_bit_of_everyt
    
func AUniqueIndexByAKey(ctx context.Context, db DB, aKey sql.NullInt64) (*AUniqueIndex, error) {
	// query
	const sqlstr = `SELECT ` +
		`a_key ` +
		`FROM a_bit_of_everything.a_unique_index ` +
		`WHERE a_key = :1`
	// run
	logf(sqlstr, aKey)
	aui := AUniqueIndex{}
	if err := db.QueryRowContext(ctx, sqlstr, aKey).Scan(&aui.AKey); err != nil {
		return nil, logerror(err)
	}
	return &aui, nil
}