SAMPLE(recordset, interval [, which ] [, UNORDERED | ORDERED( bool ) ] [, STABLE | UNSTABLE ] [, PARALLEL [ ( numthreads ) ] ] [, ALGORITHM( name ) ] )
| recordset | The set of records to sample. This may be the name of a dataset or a record set derived from some filter condition, or any expression that results in a derived record set. |
| interval | The interval between records to return. |
| which | Optional. An integer specifying the ordinal number of the sample set to return. This is used to obtain multiple non-overlapping samples from the same recordset. |
| UNORDERED | Optional. Specifies the output record order is not significant. |
| ORDERED | Specifies the significance of the output record order. |
| bool | When False, specifies the output record order is not significant. When True, specifies the default output record order. |
| STABLE | Optional. Specifies the input record order is significant. |
| UNSTABLE | Optional. Specifies the input record order is not significant. |
| PARALLEL | Optional. Try to evaluate this activity in parallel. |
| numthreads | Optional. Try to evaluate this activity using numthreads threads. |
| ALGORITHM | Optional. Override the algorithm used for this activity. |
| name | The algorithm to use for this activity. Must be from the list of supported algorithms for the SORT function's STABLE and UNSTABLE options. |
| Return: | SAMPLE returns a set of records. |
The SAMPLE function returns a sample set of records from the nominated recordset.
Example:
personRecord := RECORD
STRING UID;
STRING first_name;
STRING last_name;
STRING address;
STRING city;
STRING state;
STRING zip;
END;
person := DATASET([{'923','James','Jones','123 Elm Street','Hollywood','FL','33022'},
{'924','Sally','Jones','22 Main Street','Tampa','FL','33604'},
{'925','Jose','Gomez','111 Biscaya Lane','Miami','FL','33101'},
{'926','Adam','Wesson','77 Sunset Blvd','Boston','MA','02108'},
{'927','Evelyn','Murray','740 SW 10th Street','Boston ','MA','02116'},
{'928','Tom','Murray','740 SW 10th Street','Boston ','MA','02116'},
{'929','Joe','Yung','7511 Simson Avenue','Chicago','IL','60131'}], personRecord);
MySample1 := SAMPLE(Person,3,1); // returns every 3rd record
SomeFile := DATASET([{'A'},{'B'},{'C'},{'D'},{'E'},
{'F'},{'G'},{'H'},{'I'},{'J'},
{'K'},{'L'},{'M'},{'N'},{'O'},
{'P'},{'Q'},{'R'},{'S'},{'T'},
{'U'},{'V'},{'W'},{'X'},{'Y'}],
{STRING1 Letter});
MySample2 := SAMPLE(SomeFile,5,1); // returns A, F, K, P, U
OUTPUT(MySample1);
OUTPUT(MySample2);