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POHow to check if a column data from table exist in the same table?
 

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  1. POHow to check if a column data from table exist in the same table?
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    <p>How can I do this in SQL select statement..</p> <p>Considering I have this table</p> <pre><code>ID_A - DATE1 - DATE2 ===================== CD99 - 11/25 - 12/08 AB23 - 11/20 - 11/22 AB23 - 11/22 - 12/01 XP72 - 11/23 - 12/08 </code></pre> <p>You will notice that ID_A=AB23 has two entries and <strong>DATE2 of first line is equal to DATE1 of the second line</strong>, this means that these two lines are connected.</p> <p><strong>So, how can I get or create my select statement to view these lines that are connected to each other?</strong></p> <p>EDIT: What I was trying to do in my select statement is this: a. check DATE2 if is not null b. from there, check DATE2 if it exists in the DATE1 of whole table and return the value of columns.</p> <p>What I would like to get should look like this:</p> <pre><code>ID_A - DATE1 - DATE2 ===================== AB23 - 11/20 - 11/22 AB23 - 11/22 - 12/01 </code></pre> <p>P.S. I was hoping to not do this using a loop.. As this tend to get the server too slow to respond when I get to have too much of data. - Let me note that i am comparing columns within the same database..</p> <p>@fthiella here is my sample data with the scenario im referring to..</p> <pre><code>ID_A - DATE1 - DATE2 ===================== CD99 - 11/25 - 12/08 AB23 - 11/20 - 11/22 AB23 - 11/22 - 12/01 XP72 - 11/23 - 12/08 PQ10 - 11/20 - -n/a- LM88 - 11/21 - -n/a- PQ10 - 11/15 - 11/20 </code></pre> <p>from there i would like to get these:</p> <pre><code>ID_A - DATE1 - DATE2 ===================== CD99 - 11/25 - 12/08 AB23 - 11/22 - 12/01 XP72 - 11/23 - 12/08 </code></pre> <p>here's a quick explanation of why i excluded the others:</p> <pre><code>ID_A - DATE1 - DATE2 ===================== CD99 - 11/25 - 12/08 - not excluded AB23 - 11/20 - 11/22 - excluded because DATE2 is connected to DATE1 of same ID_A AB23 - 11/22 - 12/01 - not excluded XP72 - 11/23 - 12/08 - not excluded PQ10 - 11/20 - -n/a- - excluded because DATE2 is null LM88 - 11/21 - -n/a- - excluded because DATE2 is null PQ10 - 11/15 - 11/20 - excluded because DATE2 is connected to DATE1 of same ID_A (regardless if DATE2 of that line is null) </code></pre> <p>priority of condition can be - exclude null DATE2 first, then check comparison and exclude those lines that are preceeding other lines..</p> <p>Sorry for having so much of your time, I really appreciate every help you have given me.. for now this question can be tagged as ANSWERED, thanks again fthiella..</p>
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    1. USE-r Gabriel Doronila
    1. USE-r Gabriel Doronila
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    1. This table or related slice is empty.
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      1. POHow to check if a column data from table exist in the same table?
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      1. POHow to check if a column data from table exist in the same table?
      1. This table or related slice is empty.
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      1. POHow to check if a column data from table exist in the same table?
      1. This table or related slice is empty.
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    1. COU can use `ORDER BY` and do not worry about the line. example `ORDER BY ID_A, DATE1`. It will automatically get the result in desired order.
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      1. POHow to check if a column data from table exist in the same table?
      1. USTalha Ahmed Khan
    2. COIf I use ORDER BY, I would still see the other two lines in the above example, right? Can you give me a select statement that I could try? What I wish to have are only the lines that are connected.. Thanks for quick reply.. =)
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      1. POHow to check if a column data from table exist in the same table?
      1. USE-r Gabriel Doronila
    3. COWhy do you have set the VB.NET tag? Do you want a sql based answer or a coded one is acceptable?
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      1. USSteve
 

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