FirstSortedValue() returns the value from the expression specified in value that corresponds to the result of sorting the sort_weight argument, taking into account rank, if specified. If more than one resulting value shares the same sort_weight for the specified rank, the function returns NULL.
The sorted values are iterated over a number of records, as defined by a group by clause, or aggregated across the full data set if no group by clause is defined.
Syntax:
Return data type: dual
Arguments:
| Argument | Description |
|---|---|
| value Expression | The function finds the value of the expression value that corresponds to the result of sorting sort_weight. |
| sort-weight Expression | The expression containing the data to be sorted. The first (lowest) value of sort_weight is found, from which the corresponding value of the value expression is determined. If you place a minus sign in front of sort_weight, the function returns the last (highest) sorted value instead. |
| rank Expression |
By stating a rank "n" larger than 1, you get the nth sorted value. |
| distinct |
If the word DISTINCT occurs before the function arguments, duplicates resulting from the evaluation of the function arguments are disregarded. |
Examples and results:
Add the example script to your document and run it. Then add, at least, the fields listed in the results column to a sheet in our document to see the result.
Example 1:
Temp:
LOAD * inline [
Customer|Product|OrderNumber|UnitSales|CustomerID
Astrida|AA|1|10|1
Astrida|AA|7|18|1
Astrida|BB|4|9|1
Astrida|CC|6|2|1
Betacab|AA|5|4|2
Betacab|BB|2|5|2
Betacab|DD|12|25|2
Canutility|AA|3|8|3
Canutility|CC|13|19|3
Divadip|AA|9|16|4
Divadip|AA|10|16|4
Divadip|DD|11|10|4
] (delimiter is '|');
FirstSortedValue:
LOAD Customer,FirstSortedValue(Product, UnitSales) as MyProductWithSmallestOrderByCustomer Resident Temp Group By Customer;
| Result field (Customer) | Result value (MyProductWithSmallestOrderByCustomer) |
|---|---|
| Astrida | CC |
| Betacab | AA |
| Canutility | AA |
| Divadip | DD |
The function sorts UnitSales from smallest to largest, looking for the value of Customer with the smallest value of UnitSales, the smallest order.
Because CC corresponds to the smallest order (value of UnitSales=2) for customer Astrida. AA corresponds to the smallest order (4) for customer Betacab, AA corresponds to the smallest order (8) for customer Canutility, and DD corresponds to the smallest order (10) for customer Divadip.
Example 2:
Given that the Temp table is loaded as in the previous example:
LOAD Customer,FirstSortedValue(Product, -UnitSales) as MyProductWithLargestOrderByCustomer Resident Temp Group By Customer;
| Result field (Customer) | Result value (MyProductWithLargestOrderByCustomer) |
|---|---|
| Astrida | AA |
| Betacab | DD |
| Canutility | CC |
| Divadip | - |
A minus sign precedes the sort_weight argument, so the function sorts the largest first.
Because AA corresponds to the largest order (value of UnitSales:18) for customer Astrida, DD corresponds to the largest order (12) for customer Betacab, and CC corresponds to the largest order (13) for customer Canutility. There are two identical values for the largest order (16) for customer Divadip, therefore this produces a null result.
Example 3:
Given that the Temp table is loaded as in the previous example:
LOAD Customer,FirstSortedValue(distinct Product, -UnitSales) as MyProductWithSmallestOrderByCustomer Resident Temp Group By Customer;
| Result field (Customer) | Result value (MyProductWithLargestOrderByCustomer) |
|---|---|
| Astrida | AA |
| Betacab | DD |
| Canutility | CC |
| Divadip | AA |
This is the same as the previous example, except the distinct qualifier is used. This causes the duplicate result for Divadip to be disregarded, allowing a non-null value to be returned.
