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81 lines
2.7 KiB
HTML
81 lines
2.7 KiB
HTML
<p>Table: <code>Visits</code></p>
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<pre>
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+-------------+---------+
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| Column Name | Type |
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+-------------+---------+
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| visit_id | int |
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| customer_id | int |
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+-------------+---------+
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visit_id is the primary key for this table.
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This table contains information about the customers who visited the mall.
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</pre>
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<p> </p>
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<p>Table: <code>Transactions</code></p>
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<pre>
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+----------------+---------+
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| Column Name | Type |
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+----------------+---------+
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| transaction_id | int |
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| visit_id | int |
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| amount | int |
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+----------------+---------+
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transaction_id is the primary key for this table.
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This table contains information about the transactions made during the visit_id.
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</pre>
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<p> </p>
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<p>Write an SQL query to find the IDs of the users who visited without making any transactions and the number of times they made these types of visits.</p>
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<p>Return the result table sorted in <strong>any order</strong>.</p>
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<p>The query result format is in the following example.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong>
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Visits
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+----------+-------------+
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| visit_id | customer_id |
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+----------+-------------+
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| 1 | 23 |
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| 2 | 9 |
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| 4 | 30 |
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| 5 | 54 |
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| 6 | 96 |
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| 7 | 54 |
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| 8 | 54 |
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+----------+-------------+
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Transactions
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+----------------+----------+--------+
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| transaction_id | visit_id | amount |
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+----------------+----------+--------+
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| 2 | 5 | 310 |
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| 3 | 5 | 300 |
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| 9 | 5 | 200 |
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| 12 | 1 | 910 |
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| 13 | 2 | 970 |
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+----------------+----------+--------+
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<strong>Output:</strong>
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+-------------+----------------+
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| customer_id | count_no_trans |
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+-------------+----------------+
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| 54 | 2 |
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| 30 | 1 |
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| 96 | 1 |
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+-------------+----------------+
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<strong>Explanation:</strong>
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Customer with id = 23 visited the mall once and made one transaction during the visit with id = 12.
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Customer with id = 9 visited the mall once and made one transaction during the visit with id = 13.
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Customer with id = 30 visited the mall once and did not make any transactions.
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Customer with id = 54 visited the mall three times. During 2 visits they did not make any transactions, and during one visit they made 3 transactions.
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Customer with id = 96 visited the mall once and did not make any transactions.
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As we can see, users with IDs 30 and 96 visited the mall one time without making any transactions. Also, user 54 visited the mall twice and did not make any transactions.
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</pre>
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