PHP. Руководство по PHP. 2005
mysqli_error
mysqli_error
Description
Procedural style:string mysqli_error (mysqli link)
Object oriented style (property)class mysqli {
string error
}
The mysqli_error() function is identical to the corresponding mysqli_errno() function in every way, except instead of returning an integer error code the mysqli_error() function will return a string representation of the last error to occur for the database connection represented by the link parameter. If no error has occured, this function will return an empty string.