Aggregation & Grouping
Aggregate Functions
COUNT, SUM, AVG, MIN, MAX
💡 Aggregate, functions, EK, "CALCULATOR" jaisa, hai — MULTIPLE, rows, ke, values, ko, EK, SINGLE, summary, value, mein, "CRUNCH" kiya, jaata hai (jaise, TOTAL, AVERAGE, ya, COUNT).
COUNT(*), rows, ki, COUNT, deta hai. SUM(), NUMERIC, values, ka, TOTAL, deta hai. AVG(), average, calculate, karta hai. MIN()/MAX(), SMALLEST/LARGEST, value, RETURN, karte, hain.
Aggregate, functions, KABHI, GROUP BY, ke, BINA, bhi, use, ho, sakte, HAIN — POORE, table, ke, liye, EK, single, aggregate, RESULT, deta hai.
SELECT
COUNT(*) AS total_orders,
SUM(amount) AS total_revenue,
AVG(amount) AS avg_order_value,
MAX(amount) AS biggest_order
FROM orders;➗
Aggregate, functions, EK, "CALCULATOR" jaisa, hai — MULTIPLE, rows, ke, values, ko, EK, SINGLE, summary, value, mein, "CRUNCH" kiya, jaata hai (jaise, TOTAL, AVERAGE, ya, COUNT).
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⚡ Quick Recap
- COUNT, SUM, AVG, MIN, MAX = common, aggregate, functions
- GROUP BY, ke, saath, ya, bina, dono, use, ho, sakte, hain
- COUNT(*) vs COUNT(column) — NULL, values, ka, handling, DIFFERENT, hai
Is page mein (2 subtopics)
GROUP_CONCAT(), EK, group, ke, SAARE, values, ko, EK, SINGLE, comma-separated, string, mein, COMBINE, karta hai — jaise, EK, customer, ke, SAARE, order, IDs, ko, EK, string, mein, DIKHANA.
SELECT customer_id, GROUP_CONCAT(order_id) AS all_orders
FROM orders GROUP BY customer_id;COUNT(DISTINCT column_name), sirf, UNIQUE, values, ki, count, deta hai — jaise, EK, orders, table, mein, KITNE, DIFFERENT, customers, ne, order, kiya, ye, jaanne, ke, liye.
Tip: COUNT(DISTINCT col), COUNT(col), se, SLOWER, ho, sakta hai, badi, tables, PAR — kyunki, MySQL, ko, uniqueness, check, karne, ke, liye, EXTRA, kaam, karna, PADТA, hai.