MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -UNBOUNDED PRECEDING indicates that the window starts at the first row of the partition; offset PRECEDING indicates that the window starts a number of rows equivalent to the value of offset before the current row. UNBOUNDED PRECEDING is the default. CURRENT ROW indicates the window begins or ends at the current row.

Detailed explanation-2: -As the first term after the ROWS keyword in a window Frame specification, UNBOUNDED PRECEDING means that the starting boundary is the first row in the partition, and UNBOUNDED FOLLOWING means that the ending boundary is the last row in the partition.

Detailed explanation-3: -UNBOUNDED PRECEDING is the same as BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW . n PRECEDING is the same as BETWEEN n PRECEDING AND CURRENT ROW . n FOLLOWING is the same as BETWEEN CURRENT ROW AND n FOLLOWING . UNBOUNDED FOLLOWING is the same as BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING .

Detailed explanation-4: -UNBOUNDED PRECEDING tells the windowing function and aggregates to use the current value, and all values in the partition before the current value. UNBOUNDED FOLLOWING as follows, this means the use the current row, and consider all rows after the current row in the current partition.