Aggregate your data
COUNT counts, SUM totals, AVG averages, MIN and MAX find extremes. COUNT(*) counts rows; COUNT(column) skips NULL in that column. Most aggregates ignore NULL inputs.
हिन्दी में समझें
COUNT गिनता, SUM जोड़ता, AVG औसत, MIN और MAX सीमाएँ निकालते हैं। COUNT(*) पंक्तियाँ, COUNT(column) गैर-NULL मान गिनता है।
अभ्यास: products से COUNT(*) को total और SUM(price) को total_price दिखाएँ।
Hinglish mein samjhein
COUNT count, SUM total, AVG average, MIN/MAX extremes dete hain. COUNT(*) rows ginta hai; COUNT(column) NULL skip karta hai.
Practice: products se COUNT(*) AS total aur SUM(price) AS total_price lo.
A small SQL example
SELECT COUNT(*) AS products, AVG(price) AS avg_price FROM products;Examples use the fictional shop database bundled with the SQL playground: customers, products, orders, order_items and employees. The engine is SQLite; other SQL dialects may differ.
Try this example in the SQL playground →Practise this idea
Return COUNT(*) as total and SUM(price) as total_price from products.
Check answer & explanation
SELECT COUNT(*) AS total, SUM(price) AS total_price FROM products;COUNT(*) counts all product rows. SUM(price) adds the non-NULL prices into a single total.
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Check your understanding
COUNT(column) skips…
Check the quiz answer
NULL values
COUNT counts, SUM totals, AVG averages, MIN and MAX find extremes. COUNT(*) counts rows; COUNT(column) skips NULL in that column. Most aggregates ignore NULL inputs.
References & corrections
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