LEAD
WindowAccesses data from a subsequent row in the result set.
Syntax
LEAD(col, offset, default) OVER (ORDER BY col)
Example
SELECT name, salary, LEAD(salary) OVER (ORDER BY salary) as next_salary FROM employees;
About SQL LEAD
The LEAD keyword belongs to the Window category of SQL statements. Accesses data from a subsequent row in the result set. Understanding this command is essential for any developer working with relational databases like PostgreSQL, MySQL, SQLite, or SQL Server.
SQL (Structured Query Language) is the standard language for managing and querying relational databases. The LEAD statement is supported across all major database systems, though specific syntax may vary slightly between PostgreSQL, MySQL, MariaDB, Oracle, SQL Server, and SQLite. Always consult your database's documentation for vendor-specific features and limitations.
Best practices for using LEAD: always test queries on a development database before running them in production, use parameterized queries to prevent SQL injection, and leverage EXPLAIN to understand query performance. For complex queries, consider using CTEs (Common Table Expressions) to improve readability and maintainability.