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POReservation system - Available tables
 

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  1. POReservation system - Available tables
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    <p>I've been working on this for a few days and I can't figure it out. Ill hope you can help me out.</p> <p>I'm working on a reservation system, I would like to check if there are table's availbe on DATE and TIME. This is how my database looks like.</p> <p><img src="https://i.stack.imgur.com/vbZ9V.png" alt="enter image description here"></p> <p>I would like to put the available tables into a select dropdown menu, so on the website it only shows available tables.</p> <p>If I use the following query I can get the reserverd tables</p> <pre><code>SELECT res.reserveringsnr, datum, begintijd, eindtijd, tafr.tafelnr FROM reserveringen AS res INNER JOIN tafels_regel AS tafr ON res.reserveringsnr = tafr.reserveringsnr WHERE (res.datum = "2013/12/18" AND (res.begintijd BETWEEN "12:00:00" and "14:00:00")) </code></pre> <p>So that query put's out the reserverd table's, but here's where I'm stuck. I have no idea how to check if a certain table is reserverd on DATE and TIME.</p> <p>(NOTE: The date and time will be filled in by an variable, but for the example I used just text)</p> <h2>Edit: Working on @sebt his solution</h2> <p>First of all, to answer your questions</p> <ol> <li>Reservations are always on the same day</li> <li>A reservation has a fixed time, 2 hours always.</li> </ol> <p>I've edited sebt's his query to my values:</p> <pre><code> SELECT t.* FROM tafels t LEFT JOIN (SELECT tafelnr FROM tafels_regel tf INNER JOIN reserveringen res ON tf.reserveringsnr=res.reserveringsnr WHERE res.datum="2012/01/12" AND res.begintijd&lt;"19:00:00" AND res.eindtijd&gt;"21:00:00" ) ReservationsAtThisTime ON t.tafelnr=ReservationsAtThisTime.tafelnr WHERE ReservationsAtThisTime.tafelnr IS NULL </code></pre> <p>This query output's the following result <img src="https://i.stack.imgur.com/tbBV1.png" alt="enter image description here"></p> <p>As you can see, the query results shows all tafels (12). </p> <p>I've also exported the tables reserveringen, tafels_regel and tafels to an .csv (see edited .csv below)</p> <h2>EDIT 2:</h2> <p>Well I've edited my query again, it works for a part. This is the query (<a href="http://s9.postimage.org/i35e5bin3/querryryryreyry.png" rel="nofollow noreferrer">Screenshot</a>)</p> <pre><code> SELECT t.* FROM tafels t LEFT JOIN (SELECT tafelnr FROM tafels_regel tf INNER JOIN reserveringen res ON tf.reserveringsnr=res.reserveringsnr WHERE res.datum="2013/01/12" AND res.begintijd &lt;= "19:00:00" AND res.eindtijd &gt;= "21:00:00" ) ReservationsAtThisTime ON t.tafelnr=ReservationsAtThisTime.tafelnr WHERE ReservationsAtThisTime.tafelnr IS NULL </code></pre> <p>There are 2 reservations on 2013/01/12. (<a href="http://nivali.com/reserverings_systeem.csv" rel="nofollow noreferrer">Download</a> edited .csv)</p> <p>Reservation 1: from 19:00 to 21:00 on tafel 1</p> <p>Reservation 2: from 20:00 to 22:00 on tafel 11 and tafel 12</p> <p>When I run the query above, the only tafel not showing is tafel 1, since tafel 1 is reserverd from 19:00 till 21:00. But however, from 20:00 till 22:00 tafel 11 and 12 are also reserverd. </p> <p>As you can see in the query results, only tafel 1 is reserverd. But when I would make another reservervation from 19:00 till 21:00 and I'm checking for available tafels, then tafel 11 and tafel 12 still shows. </p> <p>The tafel will be free at 19:00, that's right, but since we always sit 2 hours we can't sit there. </p> <p>Thanks again @sebt for your input, ill hope you can help me further with this query!</p> <h2>Problem solved</h2> <p>Thanks for all the help, this is the final query</p> <pre><code>SELECT t.* FROM tafels t LEFT JOIN (SELECT tafelnr FROM tafels_regel tf INNER JOIN reserveringen res ON tf.reserveringsnr=res.reserveringsnr WHERE res.datum="2013/01/12" AND res.eindtijd &gt; "19:00:00" AND res.begintijd &lt; "21:00:00" ) ReservationsAtThisTime ON t.tafelnr=ReservationsAtThisTime.tafelnr WHERE ReservationsAtThisTime.tafelnr IS NULL </code></pre>
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    1. USNiek van der Linden
    1. USNiek van der Linden
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    1. COi'didnt understood your question.is this query is giving you a problem..?
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    2. COI'm going to try the solution below, If that solution fails, ill try to explain my question in a different way.
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      1. USNiek van der Linden
 

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