Sql script to find invalid email addresses

SELECT * FROM students WHERE email NOT LIKE '%_@__%.__%'

Get Drive Space information in sql

exec xp_fixeddrives

how to get last record value in sql server without using MAX/TOP clause?

1)SELECT * FROM  tablename WHERE  primarykeyid= IDENT_CURRENT('tablename')

Eg:

SELECT * FROM  tbl_emp WHERE  empid= IDENT_CURRENT('tbl_emp ')

2)

set rowcount 1 

select * from  tbl_emp order by empid desc

SET ROWCOUNT { number | @number_var } 

Causes SQL Server to stop processing the query after the specified number of 
rows are returned.

sql - Check length of a string

Length of VARCHAR fields the function LEN(varcharfield) is useful.

Length of TEXT fields the function is DATALENGTH(textfield). Len will not work for text field.

Example:

SELECT LEN(yourvarcharfield) AS VarcharFieldSize
SELECT DATALENGTH(yourtextfield) AS TEXTFieldSize