SQL Practice
SQL 75
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Basics & Filtering Aggregation & Grouping Joins (All Types) Subqueries & Correlated CTEs & Adv. Subqueries Window Functions Advanced & Tricky Schema Design & Opt.
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345. LAG() Previous Salary

Hard TCS Window Functions
Query Rules
  • The query columns and order must match the expected result schema.
  • NULL values should be handled appropriately where applicable.
  • The grader compares output values and sorting order to evaluate.

Schema Browser

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locations
3 cols
departments
3 cols
employees
6 cols
orders
6 cols

Reference Solution

Expected SQL 
SELECT emp_id, name, salary, LAG(salary) OVER (ORDER BY emp_id) AS prev_salary FROM employees;
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Console Output

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