The meaning of 'units' here depends on the The boundary is a row that is 'units' prior to must be a non-negative constant numeric expression. There are five ways to describe starting and ending frame boundaries: Looking for expression values that are within some band of

The RANGE frame type determines the extent of a frame by The difference is that ROWS counts individual The ROWS and GROUPS frame types are similar in that theyīoth determine the extent of a frame by counting relative to Range of the value of X for the current row. RANGE frame type, the elements of the frame are determined byĬomputing the value of expression X for all rows in the partitionĪnd framing those rows for which the value of X is within a certain The RANGE frame type requires that the ORDER BY clause of the In other words, a group consists of all peers of a row. The IS operator is true when comparing the two values.) The GROUPS frame type means that the starting and ending boundariesĪre determine by counting 'groups' relative to the current group.Ī 'group' is a set of rows that all have equivalent values for allĪll terms of the window ORDER BY clause. The ROWS frame type means that the starting and ending boundariesįor the frame are determined by counting individual rows relative The frame type determines how the starting and ending boundaries There are three frame types: ROWS, GROUPS, and RANGE. Group_concat(b, '.') OVER (ORDER BY c) AS group_concat The following SELECT statement returns: - a | b | c | group_concat Window-function processing is performed separately for each partition. Then the entire result set of the query is a single partition. Of all rows that have the same value for all terms of the PARTITION BY clause Of a query is divided into one or more 'partitions'. It is also possible toĬreate user-defined aggregate window functions.įor the purpose of computing window functions, the result set The result of group_concat(b, '.')īe used as aggregate window functions. Where rows are sorted according to the ORDER BY clause in theįor example, the frame for the row with (a=3) consists of rows (2, 'B', 'two'), Previous row ('1 PRECEDING') and the following row ('1 FOLLOWING'), inclusive, In the example above, the window frame consists of all rows between the ORDER BY a ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING The following SELECT statement returns: - a | b | group_concat Here is an example using the built-in row_number()

Window functions cannot be added by the application. That exhibit the exceptional properties found in the built-in Handling in the query planner and hence new window functions The built-in window functions, however, require special-case

The sqlite3_create_window_function() interface. Furthermore, all of the built-inĪggregate functions of SQLite can be used as anĪggregate window function by adding an appropriate OVER clause.Īpplications can register new aggregate window functions using Every aggregate window functionĬan also work as a ordinary aggregate function, simply by omitting Unlike ordinary functions, window functionsĪlso, Window functions may only appear in the result set and in theīuilt-in window functions. Expr COLLATE collation-name DESC ASC NULLS FIRST NULLS LAST

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