तिथियों की तुलना

SQL में रिपोर्टिंग

Tyler Pernes

Learning & Development Consultant

जिन सवालों के जवाब देने हैं

Last month बनाम previous month?
Rolling 7 days?

original_table
+------------+----------+
| date       | revenue  |
|------------+----------+
| 2018-01-01 | 400      |
| 2018-01-02 | 380      |
| 2018-01-03 | 625      |
+------------+----------+

Month-over-month तुलना

LAG(value, offset) मौजूदा रो से पहले offset रो की value देता है.
LEAD(value, offset) मौजूदा रो के बाद offset रो की value देता है.

Month-over-month तुलना

चरण 1: महीने के हिसाब से revenue दिखाएँ

SELECT
    DATE_PART('month',date) AS month,
    SUM(revenue) as current_rev
FROM original_table
GROUP BY month;

चरण 2: पिछले महीने का revenue

SELECT
    DATE_PART('month',date) AS month,
    SUM(revenue) as current_rev,
    LAG(SUM(revenue)) OVER (ORDER BY DATE_PART('month',date)) AS prev_rev
FROM original_table
GROUP BY month;

Month-over-month तुलना

चरण 3: प्रतिशत बदलाव की गणना

SELECT
    DATE_PART('month',date) AS month,
    SUM(revenue) as current_rev,
    LAG(SUM(revenue)) OVER (ORDER BY DATE_PART('month',date)) AS prev_rev,
    SUM(revenue)
    /
    LAG(SUM(revenue)) OVER (ORDER BY DATE_PART('month',date))-1 AS perc_change
FROM original_table
GROUP BY month;

Month-over-month तुलना

चरण 3: प्रतिशत बदलाव की गणना

+--------+--------------+-----------+--------------+
| month  | current_rev  | prev_rev  | perc_change  |
|--------+--------------+-----------+--------------|
| 01     | 15000        | null      | null         |
| 02     | 14000        | 15000     | -.06         |
| 03     | 21000        | 14000     | .50          |
+--------+--------------+-----------+--------------+

Rolling calculations

केवल 7 रो तक सीमित रखें

नया क्लॉज़: ROWS BETWEEN

SUM(value) OVER (ORDER BY value ROWS BETWEEN N PRECEDING AND CURRENT ROW)

Rolling calculations

Rolling sum क्वेरी

SELECT 
    date,
    SUM(SUM(revenue)) OVER 
    (ORDER BY date ROWS BETWEEN 6 PRECEDING AND CURRENT ROW) AS weekly_revenue
FROM original_table
GROUP BY date;

नई टेबल: web_data

web_data
+------------+-------------+--------+
| date       | country_id  | view   |
|------------+-------------+--------|
| 2018-01-01 | 1           | 24313  |
| 2018-01-01 | 2           | 3768   |
| 2018-01-01 | 3           | 26817  |
+------------+-------------+--------+

अभ्यास करते हैं!

SQL में रिपोर्टिंग