1) Using * in your query * means all columns if there is no filtering or where condition then it fetches all rows 2) Use of quotes use single quote ' ' to add space for concatenation in the query use double quote "Customer Name" for AS names else it cannot run with a space in the query. use concat function: SELECT concat(firstname, ' ' , lastname) as "Customer Name" from table cannot concat char + int. we need to CAST datatype to be the same type. 3) To get Top entries SELECT TOP - This allows us to limit the number or percentage of rows returned by a query. eg. SELECT TOP n where n is a number eg SELECT TOP 10 or TOP n Percent eg. SELECT TOP 10 Percent eg. SELECT TOP n WITH TIES - retrieve duplicates where applicable (nondeterministic) OFFSET-FETCH is an extension to the ORDER BY clause: -allows filtering a requested range of rows -provides a mechanism for paging through results - specify a number of rows to skip, number of rows to retrieve. eg.
I hope to share with you my consolidated thoughts on a wide variety of topics here.