Please can some one explain to me the meaning of quotation marks on the

data and time functions

''SELECT * FROM MYTABLE WHERE MYDATE >= ''' + ''01/31/2012'' + '' ' ''



''SELECT * FROM MYTABLE WHERE MYDATE >= ''' +
(DT_WSTR, 255)@[System::ContainerStartTime] + '' ' ''


SELECT * FROM MYTABLE WHERE MYDATE >= ''02/22/2012 2:28:40 PM'

The above statements on the quotation mark are not making sense to me despite the explanation given on the book

The double quotes around the date, "01/31/2012", are there simply because we are building a string, and strings are delimited by double quotes in the expression builder. The author chose to separate the date from the other parts of the string because this part might easily be replaced with a variable. We are creating a SELECT statement, and in such a statement a date is delimited by single quotes. The author chose to include these single quotes in separate string elements, i.e., the left single quote in the string with SELECT, and the right single quote in a separate string appended at the3 end of the expression. The author could just as easily have written: