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POJoin two tables on one without mutyplying rows per record
 

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  1. POJoin two tables on one without mutyplying rows per record
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    <p>Let say we have 3 tables named <code>TRANSACTIONS</code>, <code>ORDERS</code>, <code>PAYMENTS</code> all of them having <code>TRANSACTION_ID</code>.</p> <p>This is the regular output I get when joining transaction that has 5 orders and 3 payments:</p> <pre><code>transaction_id, order_id, payment_id ---------- 1, 20, 35 1, 20, 36 1, 20, 37 1, 21, 35 1, 21, 36 1, 21, 37 .... </code></pre> <p>What I should get is:</p> <pre><code>transaction_id, order_id, payment_id ---------- 1, 20, 35 1, 21, 36 1, 22, 37 1, 23, null 1, 24, null </code></pre> <p>If there are more payments than orders, it should have <code>NULL</code> in the <code>order_id</code> column.</p> <p>Basically I need to have number of rows per <code>transaction_id</code> equal to the bigger number of count of <code>orders</code>/<code>payments</code> (in this example 5 > 3 so 5).</p> <p>Have in mind that each of these tables have couple of million records.</p> <p><strong>EDIT</strong>:</p> <p>By the request in the comment, above query is simple join</p> <pre><code>SELECT t.transaction_id, o.order_id, p.payment_id FROM TRANSACTION t LEFT JOIN ORDERS o on o.transaction_id = t.transaction_id LEFT JOIN PAYMENTS p on p.transaction_id = o.transaction_id </code></pre> <p><strong>EDIT 2</strong>:</p> <p>I cannot disclose full table schemes, I only wrote columns essential for the query to work. In reality every of those tables has 20+ columns, and the query should return a combined total of around 20 columns. Again, <code>TRANSACTIONS</code> has over 100m records, and both <code>ORDERS</code> and <code>PAYMENTS</code> have 150m+ records of which we need around 100k records to be returned.</p>
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    1. USDusan Vasiljevic
    1. USDusan Vasiljevic
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    1. COCan you post your SQL query?
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      1. USChristoph Walesch
    2. COCould you show tables example
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      1. USvalex
 

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