</>
sqlbeginner

Handle NULLs with COALESCE

Use COALESCE to replace NULL values with a default in SQL queries.

sql
-- Replace NULL with a default value
SELECT
  employee_id,
  first_name,
  COALESCE(phone, 'N/A') AS phone,
  COALESCE(department, 'Unassigned') AS department
FROM employees;

-- Chain multiple fallbacks
SELECT
  product_id,
  COALESCE(sale_price, retail_price, wholesale_price, 0) AS effective_price
FROM products;

Use Cases

  • Replacing NULL values in reports
  • Default values for missing data

Tags

#sql#coalesce#null#default-value

Related Snippets

Similar patterns you can reuse in the same workflow.

sqladvanced

Recursive CTE for Hierarchical Data

Query hierarchical data like org charts, categories, and file trees using recursive CTEs.

Best for: Querying organizational hierarchies

#sql#cte
sqlintermediate

SQL Pivot and Crosstab Queries

Transform row data into columnar reports using CASE expressions, FILTER, and crosstab patterns.

Best for: Creating monthly revenue reports

#sql#pivot
sqlintermediate

SQL Upsert and Merge Patterns

Insert or update records atomically using ON CONFLICT, MERGE, and database-specific upsert syntax.

Best for: Syncing data from external sources

#sql#upsert
sqladvanced

SQL Index Strategy Patterns

Create effective indexes including composite, partial, covering, and expression-based indexes.

Best for: Optimizing slow database queries

#sql#indexes