anchor.diff:  , VARIANCE (salary) OVER (PARTITION BY deptnum ORDER BY empnum ROWS UNBOUNDED PRECEDING)
   FROM persnl.employee;
   ```
  -
  -
  
positive.code: 
  * The window frame units can only be ROWS. RANGE is not supported by
  {project-name}. An attempt to use RANGE will result in a syntax error.
  
  * The ANSI _window-frame-exclusion-specification_ is not supported by
  {project-name}. An attempt to use a _window-frame-exclusion-specification_
  will result in a syntax error.
  
  * Multiple _inline-window-specifications_ in a single SELECT clause are
  not supported. For each window function within a SELECT clause, the
  
negative.code: [[olap_functions]]
  = OLAP Functions
  
  On-line Analytical Process (OLAP) functions provide the capability to partition source data into groups of rows, order the rows in each group, compute aggregates within a window frame for a row. Typically, an OLAP function in SQL is expressed in two components <FUNCTION> and <OVER>: <FUNCTION> specifies the function and the arguments, and <OVER> specifies the partitioning, the ordering and the window frames. <OVER> is sometimes called the window. OLAP functions are used to perform analytic tasks against data sets stored in or computed from a set of tables, such as moving average and ranks.
  
  Trafodion also supports a set of sequence functions which are SQL extensions and have to be used together with a SEQUENCE BY clause. These sequence functions can be used to compute a running quantity of a column up to and include the current row as follows.
  
  * `RUNNINGAVG (column-expression)`: returns the average of non-null values. For more information, see <<runningavg_function,RUNNINGAVG Function>>.
  * `RUNNINGCOUNT{(*) | (column-expression)}`: returns the number of rows up to and including the current row. For more information, see <<runningcount_function,RUNNINGCOUNT Function>>.
  * `RUNNINGMAX(column-expression)`: returns the maximum of values of a column expression up to and including the current row. For more information, see <<runningmax_function,RUNNINGMAX Function>>.
  * `RUNNINGMIN(column-expression)`: returns the minimum of values of a column expression up to and including the current row. For more information, see <<runningmin_function,RUNNINGMIN Function>>.
  * `RUNNINGRANK(expression)`: Returns the rank of the given value of an intermediate result table ordered by a SEQUENCE BY clause in a SELECT statement. For more information, see <<runningrank_function,RUNNINGRANK Function>>.
  * `RUNNINGSTDDEV(column-expression)`: returns the standard deviation of non-null values of a column expression up to and including the current row. For more information, see <<runningstddev_function,RUNNINGSTDDEV Function>>.
  * `RUNNINGSUM(column-expression)`: returns the sum of non-null values of a column expression up to and including the current row. For more information, see <<runningsum_function,RUNNINGSUM Function>>.
  * `RUNNINGVARIANCE(column-expression)`: returns the variance of non-null values of a column expression up to and including the current row. For more information, see <<runningvariance_function,RUNNINGVARIANCE Function>>.
  
  This section describes the syntax and semantics of the OLAP window functions. The OLAP window functions
  are ANSI compliant.
  
  [[considerations_for_window_functions]]
  