Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Each attribute is actually a distinct entity in this model, but they are all sharing the same storage in the same physical table (Why?). This yields:</p> <pre><code>with data as ( select entity = 1, attribute = 'ben', attributeType=1, enddate = convert(datetime,'99990101') union all select entity = 1, attribute = 'alt', attributeType=2, enddate = convert(datetime,'99990101') union all select entity = 1, attribute = '12345', attributeType=3, enddate = convert(datetime,'99990101') union all select entity = 2, attribute = 'sam', attributeType=1, enddate = convert(datetime,'99990101') union all select entity = 2, attribute = 'smith', attributeType=2, enddate = convert(datetime,'99990101') union all select entity = 2, attribute = '67890', attributeType=3, enddate = convert(datetime,'99990101') union all select entity = 2, attribute = '68790', attributeType=3, enddate = convert(datetime,'20130331') union all select entity = 2, attribute = '876', attributeType=3, enddate = convert(datetime,'19810101') ) select top 1 FirstName, LastName, AccountNum from ( select top 1 a1.entity, FirstName, LastName from ( select entity, enddate, attribute as FirstName from data d where d.enddate &gt;= getdate() and attributeType = 1 ) a1 join ( select entity, enddate, attribute as LastName from data where enddate &gt;= getdate() and attributeType = 2 ) a2 on a1.entity = a2.entity and a1.enddate = a2.enddate where FirstName = 'sam' and LastName = 'smith' and a1.enddate &gt;= getdate() and a2.enddate &gt;= getdate() order by a1.enddate ) E left join ( select entity, enddate, attribute as AccountNum from data where enddate &gt;= getdate() and attributeType = 3 ) a3 on a3.entity = E.entity order by a3.enddate </code></pre> <p>returning:</p> <pre><code>FirstName LastName AccountNum --------- -------- ---------- sam smith 68790 </code></pre> <p>Note that it is quite common for accountign departments, at least, to enter future transactions during quiet times of the month, especially if those transactions will take effect during busy times of the month (ie month-end). The same for annual transactions. One should not assume that only one record can exist with an expiry > getdate().</p>
    singulars
    1. This table or related slice is empty.
    1. POSelf join with inner and outer join query
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USPieter Geerkens
    1. USPieter Geerkens
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI like the consideration about multiple valid entries, though your logic won't filter properly. Your subqueries do top 1 by enddate w/o filtering for the proper entity.
      singulars
      1. PO
      1. USJAQFrost
    2. COIt's not an optimization, it's a logic error. Top one order by enddate is the last entered by attribute type. So you get last type 1, last type 2, last type 3 and hope that they're the same entity who happens to be named sam smith. Otherwise, you return NULL.
      singulars
      1. PO
      1. USJAQFrost
    3. CO@Jason: Got it. Let me ponder for a minute.
      singulars
      1. PO
      1. USPieter Geerkens
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload