Top, Bottom, Nth Record and Random Record Queries

Description

When Alpha Anywhere performs a query, sometimes you are only interested in the top or bottom x records in query. For example you may have a query that selects all donors who have given more than $1,000, sorted by size of donation. Perhaps you only want to see the 10 biggest donors. Alpha Anywhere has several functions designed to extract the top or bottom records from a query. It also has a function designed to extract every Nth record from a query. This is useful in certain mailing list applications where you want to mail to a subset of your list. Finally, Alpha Anywhere has functions that allow you to select records at random from a table.

• BOTTOM_PERCENT_RECORDS()

  Returns the bottom Percent of records in a table for a given sort order.

• BOTTOM_RECORDS()

  Selects the bottom X% of the records in a table, for a given sort order.

• RANDOM_PERCENT_RECORDS()

  Selects X% of the records in a table at random. If the optional filter is supplied, the records are selected only from those that satisfy the filter.

• RANDOM_RECORDS()

  Selects count records at random from a table. If the optional filter is supplied, the records are selected only from those that satisfy the filter.

• SAMPLE_RECORDS()

  Selects every Nth record in a table, for a given sort order.

• TOP_PERCENT_RECORDS()

  Selects the top X% of the records in a table, for a given sort order. (Percent is expressed as a whole number, e.g. 50 for 50%).

• TOP_RECORDS()

  Selects the top count records in a table, for a given sort order. If the optional filter is supplied, only records that satisfy the filter are returned. The table's sort order is determined by the query's Order parameter.

Examples

t = table.current()
query.filter = "top_records(100)"
query.order = "donation_size"
i = t.query_create()
topparent.resynch()'synchronize the form to show the query

The following query returns the bottom 10 orders placed after May 1, 2015.

t = table.current()
query.filter = "bottom_records(10, \"orderdate > {5/1/2015}\")"
query.order = "order_total"
i = t.query_create()
topparent.resynch()

The following query returns the top 10% of students in a school

t = table.current()
query.filter = "top_precent_records(10)"
query.order = "grade_point_average"
i = t.query_create()
topparent.resynch()

The following query runs a saved query, but only shows the top 10 records selected by the query. The saved query is called "Overdue_Accounts".

t = table.current()
query.filter = "top_records(10," + query_filter_get("overdue_accounts") + ")"
query.order = ""
i = t.query_create()
topparent.resynch()

The following query selects 10% of the records in table, for state of MA.

t = table.current()
query.filter = "random_percent_records(10,\"state = 'ma' \")"
query.order = "rand()*100000"
i = t.query_create()
topparent.resynch()