title: Separate tables on sql workbench rather than a single one
body: <p>I have probably a banal question, but I need an advice.</p>
  <p>I am working for the DBMS of a center, where there are two different types of customer: let's call them <strong>customerOrdinary</strong> and <strong>customerSpecial</strong>.</p>
  <p>Of course they have attributes in common, like Name, Surname, date of birth...
  And then <strong>customerSpecial</strong> has attributes that <strong>customerOrdinary</strong> does not have and <em>viceversa</em>.</p>
  <p>customerSpecial and customerOrdinary are then connected to different tables: <strong>customerOrdinary</strong> is connected to table1, and <strong>customerSpecial</strong> is connected to table2 and table3</p>
  <p>At this point, knowing that, I have 2 different ways possible:</p>
  <p><strong>WAY 1:</strong></p>
  <p>create a single table &quot;customer&quot; with all the common attributes, and then two other tables customerS and customerO with the same PK and other columns.</p>
  <pre><code>CUSTOMER
  ID     DATEOFBIRTH.  NAME.   SURNAME.   TYPE
  01.    1989/07/12.   Sal.     Dallow.    S
  02.    1987/09/12.   Kreb.    Krusty.    O
  03.    1999/01/02.   Josh.    Milly.     S
  
  CustomerO
  ID.      NumberOfCr.   .....
  02.       18273.       .....
  
  Customer S
  ID.     DateAsmp.    DateEnd.     TypeCon
  01.     2020/12/12.  2021/10/07.    STN
  03.     2020/11/22.  2020/12/30.    PLS
  </code></pre>
  <p><strong>WAY 2</strong></p>
  <p>Create directly 2 different and separate tables, CustomerO and CustomerS:</p>
  <pre><code>CustomerS 
  ID     DATEOFBIRTH.  NAME.   SURNAME.  DateAsmp.    DateEnd.     TypeCon 
  01.    1989/07/12.   Sal.     Dallow.  2020/12/12.  2021/10/07.    STN
  03.    1999/01/02.   Josh.    Milly.   2020/11/22.  2020/12/30.    PLS
  
  
  CustomerO
  ID     DATEOFBIRTH.  NAME.   SURNAME.   NumberOfCr.  
  02.    1987/09/12.   Kreb.    Krusty.   18273.
  </code></pre>
  <hr />
  <p>Which approach do you think should I follow? why? And most important, the first approach is someway incorrect?</p>