vb.net with mysql how to pick between to dates of different years?

Question

I have a vb.net program that queries a mysql database. i can search and get records between to dates with this code:

sqlQRY12 = "SELECT * from mating WHERE date BETWEEN '" & export_daily_date_DateTimePicker1.Text & "' AND '" & export_daily_date_DateTimePicker2.Text & "' AND chkbox = '0' ORDER BY lot_id ASC"

my format for my date is:

        export_daily_date_DateTimePicker1.Format = DateTimePickerFormat.Custom
    export_daily_date_DateTimePicker1.CustomFormat = "MM/dd/yy"

    export_daily_date_DateTimePicker2.Format = DateTimePickerFormat.Custom
    export_daily_date_DateTimePicker2.CustomFormat = "MM/dd/yy"

however if i try to search between two years like 12/20/13 - 02/20/14 I return no records when i know they exist? Any help would be great ty

Answer 1

Generally dates expressed as strings in database queries should be in the format "YYYY-MM-DD".

You essentially want your executed query to be this:

SELECT * from mating
WHERE date BETWEEN '2013-12-20' AND '2014-02-20'

So change the format of your dtpickers to be yyyy-mm-dd like this:

export_daily_date_DateTimePicker1.Format = DateTimePickerFormat.Custom
export_daily_date_DateTimePicker1.CustomFormat = "yyyy-MM-dd"

export_daily_date_DateTimePicker2.Format = DateTimePickerFormat.Custom
export_daily_date_DateTimePicker2.CustomFormat = "yyyy-MM-dd"

Answer 2

You should never concatenate values into your SQL commands. If at all possible, you should use parameters. With parameters, you can specify the value as it's actual type (Date) rather than as the string representation. The ADO Provider will handle converting the value correctly for you.

cmd.CommandText = "SELECT * from mating WHERE date BETWEEN @date1 AND @date2 AND chkbox = '0' ORDER BY lot_id ASC"
cmd.Parameters.AddWithValue("@date1", export_daily_date_DateTimePicker2.Value)
cmd.Parameters.AddWithValue("@date2", export_daily_date_DateTimePicker2.Value)