SQL新手求助：Campaign表触达渠道评估及双渠道客户统计查询

Hey there! As a SQL newbie, I’ll walk you through straightforward, easy-to-understand queries to meet your two requirements using your Campaign table.

1. Evaluate Customer Reach Channels #

This query breaks down how customers are being reached across each channel, showing the count of unique customers per channel type:

SELECT 
  Channel,
  COUNT(DISTINCT "Customer ID") AS unique_customer_count
FROM Campaign
GROUP BY Channel
ORDER BY unique_customer_count DESC;

Quick breakdown: #

• COUNT(DISTINCT "Customer ID") ensures we count each customer only once per channel, even if they joined multiple campaigns through the same channel.
• GROUP BY Channel groups results by each of your three channel options (Direct Email, Email, Both).
• ORDER BY sorts results from the most to least used channel, so you can spot trends at a glance.

2. Count Customers Reached via Both Channels #

To get the number of unique customers who were reached through the "Both" channel:

SELECT 
  COUNT(DISTINCT "Customer ID") AS both_channel_customer_count
FROM Campaign
WHERE Channel = 'Both';

Quick breakdown: #

• The WHERE clause filters the table to only include records where the channel is "Both".
• COUNT(DISTINCT "Customer ID") prevents duplicate counts of the same customer, even if they have multiple campaigns tagged with "Both".

内容的提问来源于stack exchange，提问作者Hitesh Shetty