The sample prefix to a LOAD or SELECT statement is used for loading a random sample of records from the data source.
Syntax:
Sample p ( loadstatement | selectstatement )
Arguments:
| Argument | Description | 
|---|---|
| p | An arbitrary expression which valuates to a number larger than 0 and lower or equal to 1. The number indicates the probability for a given record to be read. All records will be read but only some of them will be loaded into Qlik Sense. | 
Example:
Sample 0.15 SQL SELECT * from Longtable;
Sample(0.15) LOAD * from Longtab.csv;
Information note The 
 parentheses are allowed but not required.