SQL for Testers
SQL tutorials for testers: SELECT, joins, DDL and DML, subqueries, transactions and test data checks.
SQL Window Functions: ROW_NUMBER, RANK, LAG/LEAD, NTILE and Frame Clauses
SQL window functions with examples: ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, NTILE, PERCENT_RANK, FIRST/LAST_VALUE and ROWS vs RANGE frames.
SQL CTEs and Recursive CTEs: WITH Clause Explained with Examples
Common Table Expressions in SQL: WITH syntax, chaining CTEs, CTE vs subquery vs temp table, and recursive CTEs for hierarchies and date series.
SQL Date Functions and Date Edge Cases: Working Days, Month-End, Fiscal Year, Time Zones
SQL date functions with examples, plus the edge cases interviewers ask: working days, last day of month, fiscal years, and time zones (TIMESTAMP vs DATETIME).
Semi-Joins and Anti-Joins in SQL: EXISTS, NOT EXISTS, IN, ANY and ALL
Semi-joins and anti-joins in SQL: EXISTS vs IN vs JOIN, NOT EXISTS vs NOT IN vs LEFT JOIN IS NULL, ANY and ALL, and a decision tree for choosing.
SQL Practice Projects: E-Commerce, Banking and Social Media Databases with Queries
Three SQL practice projects with schemas and real queries: an e-commerce store, a banking system and a social media app, for portfolio and interview practice.