So, this will give you a table Foo, where there is only one row and that row has an entry 437. You can use that, for other purposes also you can do a select of a literal, from a table with using a from clause where in, you will get a single column table, where as many is as there are records in the instructor will be produced.
எனவே, இது உங்களுக்கு ஒரு டேபிள் Foo ஐக் கொடுக்கும், அங்கு ஒரே ஒரு ரோ மட்டுமே உள்ளது, அந்த ரோல் 437 ரோ உள்ளது.