C# 日期时间 MySQL 命令

Question

I am having issues with using the DateTime as the parameter to work for a sql query.

Here is the query I would like:

command.CommandText = "SELECT idGameNumber FROM GameOutcome WHERE GameOutcome.gameDate = <insert DateTime game_time>";

where game_time is a DateTime object and Gameoutcome.gameDate is a DATETIME datatype.

What do I need to put on the right side of the = sign in there WHERE clause?

Answer 1

Solution 1: using DateTime string

MYSQL takes the DateTime in Following default format:

yyyy-MM-dd HH:mm:ss

so you can convert your datetime object into above format .

Try This:

command.CommandText ="SELECT idGameNumber FROM GameOutcome WHERE GameOutcome.gameDate ='"+ game_time.ToString("yyyy-MM-dd HH:mm:ss")+"'";

Solution 2: using parameterised queries .

you might have already heared about parameterised queries .
Parameterised queries not only avoid sql injection attacks they also provide clean way of sending/passing arguments to feilds in the table.

command.CommandText ="SELECT idGameNumber FROM GameOutcome WHERE GameOutcome.gameDate =@gamedate;"    
command.Parameters.AddWithValue("@gamedate",game_time);  

Answer 2

as datetime format in mysql is in yyyy-MM-dd HH:mm:ss format so to use c# DateTime and pass it in query where as parameter:

1. you can use ToString() method of DateTime variable and format the returned value as: game_time.ToString("yyyy-MM-dd HH:mm:ss")

command.CommandText = $"SELECT idGameNumber FROM GameOutcome WHERE GameOutcome.gameDate = '{game_time.ToString("yyyy-MM-dd HH:mm:ss")}'";

or you can write the interpolation simpler as:

command.CommandText = $"SELECT idGameNumber FROM GameOutcome WHERE GameOutcome.gameDate = '{game_time:yyyy-MM-dd HH:mm:ss}'";

the longer version to use:

DateTimeFormatInfo isoFormat = CultureInfo.InvariantCulture.DateTimeFormat;

dateValue.ToString(isoFormat.SortableDateTimePattern); 

dateValue.ToString(isoFormat.UniversalSortableDateTimePattern)