SQL Tutorial #25 UNDERSTANDING WINDOW FUNCTIONS IN SQL (PART-1)
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A window is basically a
A window is basically a set of rows or observations in a table or result set.
In a table you may have more than one window depending on how you specify the query.
Functions are predefined in SQL and you use them to perform operations on data.
So windows functions are SQL functions that enable us to perform operations on a window – that is, a set of records.
function(expression|column) OVER(
[ PARTITION BY expr_list optional]
[ ORDER BY order_list optional]
)
function(expression|column) is the window function
OVER() specifies that the function before it is a window function not an ordinary one.
The PARTITION BY divides the result set into different partitions/windows.
The next parameter ORDER BY is used to sort the observations in a window.
In a table you may have more than one window depending on how you specify the query.
Functions are predefined in SQL and you use them to perform operations on data.
So windows functions are SQL functions that enable us to perform operations on a window – that is, a set of records.
function(expression|column) OVER(
[ PARTITION BY expr_list optional]
[ ORDER BY order_list optional]
)
function(expression|column) is the window function
OVER() specifies that the function before it is a window function not an ordinary one.
The PARTITION BY divides the result set into different partitions/windows.
The next parameter ORDER BY is used to sort the observations in a window.
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