join.html

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            <h1>SQL JOIN</h1>

            <p>A JOIN clause is used to combine rows from two or more tables, based on a related column (primary,
                foreign key) between them.</p>

            <h2>INNER JOIN Syntax</h2>
            <pre><code class="language-sql">SELECT column_name(s)
FROM table1
JOIN table2
ON table1.column_name = table2.column_name;</code></pre>

            <h2>Example Tables</h2>
            <p>Let's look at a selection from the "unit_dose_orders" (outdated) table:</p>

            <pre><code class="language-sql">unit_dose_order_id | patient_id | dosage
1                  | 9          | 0.25 MG
2                  | 15         | 50 MG
3                  | 18         | 15</code></pre>

            <p>Then, look at a selection from the "patients" table:</p>

            <pre><code class="language-sql">patient_id | first_name | last_name
1          | Miyuki     | Riviera
2          | Deunan     | Knute
3          | Lois       | McAllister</code></pre>

            <p>Notice that the "patient_id" column in the "unit_dose_orders" table refers to the "patient_id" in the
                "patients" table. The relationship between the two tables is the "patient_id" column.</p>

            <h2>JOIN Example</h2>
            <p>The following SQL statement selects records that have matching values in both tables:</p>

            <pre><code class="language-sql">SELECT *
FROM patients p
JOIN admissions a ON a.patient_id = p.patient_id;</code></pre>

            <h2>Different Types of SQL JOINs</h2>
            <p>It is rare to need a join other than (INNER) JOIN.</p>

            <p><strong>DISCLAIMER:</strong> Our tool only supports INNER/LEFT JOIN</p>

            <p>Here are the different types of the JOINs in SQL:</p>

            <p>- (INNER) JOIN: Returns records that have matching values in both tables</p>
            <p>- LEFT (OUTER) JOIN: Returns all records from the left table, and the matched records from the right
                table</p>
            <p>- RIGHT (OUTER) JOIN: Returns all records from the right table, and the matched records from the left
                table</p>
            <p>- FULL (OUTER) JOIN: Returns all records when there is a match in either left or right table</p>

            <img src="joins.png" alt="SQL JOIN Types Diagram" style="max-width: 50%; height: auto; margin: 20px 0;">

            <h2>JOIN Three Tables</h2>
            <pre><code class="language-sql">SELECT *
FROM patients p
JOIN admissions a ON a.patient_id = p.patient_id
JOIN doctors ph ON ph.doctor_id = a.attending_doctor_id;</code></pre>
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