22 Feb 2025
π It's #SQLSaturday! Let's talk about Common Table Expressions (CTEs)βa game-changer for writing clean, readable, and recursive SQL queries.
Why use CTEs?
β
Improve query readability π
β
Avoid subquery repetition π
β
Enable recursive queries π
Basic CTE Syntax:
WITH CTE_Name AS (
SELECT column1, column2
FROM some_table
WHERE condition
)
SELECT * FROM CTE_Name;
Recursive CTEs: Perfect for hierarchical data!
WITH RecursiveCTE AS (
SELECT id, parent_id, name
FROM employees
WHERE parent_id IS NULL
UNION ALL
SELECT e.id, e.parent_id, e.name
FROM employees e
JOIN RecursiveCTE r ON e.parent_id = r.id
)
SELECT * FROM RecursiveCTE;
π‘ Pro tip: Use CTEs for breaking down complex queries into manageable parts! Who else loves CTEs? Comment below! β¬οΈ #SQL #DataEngineering
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28 Jun 2022
Video Instructions on how to build a #recursiveCTE. #CTEinSQL #CTEinSQLserver #commontableexpressions #stedmansolutions
stevestedman.com/2022/06/steβ¦
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21 Jul 2015
Working on nice #PostgreSQL / #PostGIS query: hydrant impact zone.With #KNNSearch #RecursiveCTE #NetworkAnalysis #GIS
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