Counting the Rows

Question

Hey When i m using count(*) command for counting the number of records its just not working. Is there any other way for the same? please help

Priya Linge · Answer

Hi Its working perfectly. select COUNT(*) from Customer : result will be the number of records(rows)--Answer -9 select COUNT(1) from Customer :result will be same. Hope this will help you. Thanks.

Syed Nayab Ali · Answer

Hi Alec You need to know that COUNT() is not a command it is a predefined function and every function in SQL must return atleast one value you should also mention tablename in query from where u want to count row. select count(*) from table_name select count(1) from table_name no doubt both query will give you same result but COUNT(1) is faster than COUNT(*). Suppose you have a table which has more than 100 columns and billions of records then you should use COUNT(1) in place of COUNT(*) because COUNT(1) will generate count only from one column. COUNT(*) counts every record so it takes time. you can also use column name in place of * & 1 select count(column_Name) from table_name Hope this will make ur concept clear. Thanks

Syed Nayab Ali · Answer

@Javeed .... Thanks Javeed I was not aware about that COUNT(1) do not consider NULL

Javeed M Shaikh · Answer

Hi Alec also keep in mind that Count(*) will consider NULL values also in the count and COUNT(1) will not consider NULL values so if your data contains NULL then you should consider Count(*). Also the 1 in COUNT(1) is not the column position it is an expression. Count(*) will optimize the query while counting the records by considering the Index Column. So that said if you have an Index Column in your table Count(*) and Count(1) should give the same performance.

Alec Stewart · Answer

its working..thanks