Join in SQL Server

Joins are used to extract information from more than one table based on the related column/columns means you can retrieve data from two or more tables based on logical relationships between the tables. Continue reading “Join in SQL Server”

Improve SQL Server Performance

We are going to discuss some points that help improve database performance. Always try keep this point in mind before creating new database or writing query or procedures. Continue reading “Improve SQL Server Performance”

UPDATE Statement in SQL Server

Update statement is different from INSERT and DELETE statements.UPDATE statements is used for updating a single records to multiple records. UPDATE statements use a WHERE clause, same as SELECT statement. Continue reading “UPDATE Statement in SQL Server”

Using IN in SQL Server

IN operator we use when we Determines whether a specified value matches any value in a sub query or a list. The IN operator allows you to specify multiple values in a WHERE clause.it also helps reduce the need to use multiple OR conditions. Continue reading “Using IN in SQL Server”

DATEPART() function in SQL Server

DATEPART() function returns a value equal to the part of a specified date.

Summery

DATEPART(datepart, date)

where date is the valid date or a string in date format
and datepart can be one of the following:

datepart	Abbreviation
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
weekday	dw, w
hour	hh
minute	mi, n
second	ss, s
millisecond	ms

Example

Suppose you have a table ‘tbl_employee’
tbl_employee

Employee Id	EmpName	Age	DateOfJoin
1	Ankur	28	11/04/1995
2	David	32	11/04/2002

The following query return the date of joining of the Ankur:

SELECT datepart("year", DateOfJoin)

Output will be:

—————–
1995

Now if you want to current year, you can use the following query:

SELECT DATEPART("Year",GETDATE())

–or—

SELECT DATEPART("yy",GETDATE())

GETDATE() function return the current date.

DATEDIFF() function in SQL Server

DATEDIFF() function is very useful when we are working with date operations. DATEDIFF function return the difference between date items in days, weeks, minutes, years and hours. It can also used with WHERE clause. Continue reading “DATEDIFF() function in SQL Server”

STR(), CHAR(), and ASCII() function in SQL Server

STR() function

In Sql Server STR() function converts a numeric value to character data. STR() function allows us to specify the total length and number of decimal places to be included when it is converted to character data. Continue reading “STR(), CHAR(), and ASCII() function in SQL Server”

ISNULL in SQL Server

ISNULL function replaces NULL values with the specified replacement value. you can use ISNULL as Continue reading “ISNULL in SQL Server”

SQL Having Clause

When we want to use Checking or Condition upon an aggregate column with Group By clause in Select statement then we cannot use Where statement with aggregate column, in this case we use Having clause. Continue reading “SQL Having Clause”

SQL Group by Clause

When we want to perform calculation on any column like Sum or want to use aggregate functions like Min, Max in our Select statement then we use GROUP BY statement. GROUP BY statement returns result across multiple records and group the results by one or more desired columns. Continue reading “SQL Group by Clause”