Bench Periods Between Project Allocations

SQL practice question · Hard · Gaps & Islands · Infosys, Accenture

Allocations are inclusive date ranges and can overlap or be nested (an employee can be on two projects at once). A bench period is a run of days between allocations when the employee is on no project. Report bench periods longer than 14 days that lie between two allocations (ignore time before the first and after the last allocation). Return emp_id, bench_start, bench_end (first and last day without allocation) and bench_days. Order by emp_id, bench_start.

Table: allocations

Schema of allocations
ColumnType
emp_idTEXT
project_codeTEXT
alloc_startDATE
alloc_endDATE
Sample rows of allocations
emp_idproject_codealloc_startalloc_end
E1P12026-01-012026-01-31
E1P22026-02-202026-03-31
E1P32026-04-052026-04-30
E2P42026-01-012026-03-31
E2P52026-02-012026-02-28
E2P62026-04-202026-05-31
E3P72026-01-102026-06-30
Expected output on the sample data
emp_idbench_startbench_endbench_days
E12026-02-012026-02-1919
E22026-04-012026-04-1919

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