Archive for December, 2018



Setting section height to a specific number

Monday 31 December 2018 @ 12:26 am

The section height in Crystal is an analog setting, not a digital setting. In other words you can’t go into the section expert and set the height of a section to exactly 1.25 inches. You have to go by the ruler on the side and make the adjustments visually. But if you know the secret, there is a way to force the section to be exactly the size you want. It relies on the fact that field objects have both a size setting and a position setting that you can set digitally. Here are the steps:

1) Make the section smaller than your target size.
2) Place an extra field near the top of that section.
3) Right click on the field and select “Object Size and Position”.
4) Set the “Y” property for this field to zero which puts the field at the top of the section.
5) Set the height property for this field to the desired height for the section.
6) Click ‘OK’
7) Delete the field.

When you click OK, the object will grow vertically to the desired height, forcing the section to grow. And, since the object is starting at position zero the section will be exactly the same height as the object. This makes it easy to create many sections that are all exactly the same height.




Better SQL for showing the last record

Monday 24 December 2018 @ 6:25 pm

I recently wrote about the SQL to return the last record in SQL Server. Adam Butt of APB reports wrote to remind me that if you are using in SQL Server or Oracle you can do this more efficiently using a RowNumber “Over” a Partition. He also gave me an example which has helped me understand the pieces that go into this method. There are three components:
RowNumber() will number all the rows in your results, like a Crystal running total. However, it won’t work unless you give it an OVER clause to put the records in order. The OVER clause is just an “ORDER BY clause put in parentheses right after the word OVER. This statement would number all the records in your results from 1 to n:

ROW_NUMBER() OVER( ORDER BY Order.OrdDate DESC) AS RowNum

You add one more piece when you want the Row Number to start over with each group, the “Partition By”. Partition By is similar to Group By but happens inside the OVER clause. This statement would number the records in your results from 1 to n within each Customer:

ROW_NUMBER()
OVER( PARTITION BY Customer.Name ORDER BY Order.OrdDate DESC) AS RowNum

Notice that in both cases the ORDER BY is “DESC” or descending which means the latest record for each customer will be first or Row_Number 1. We can use that in the SQL below to make sure we only see the last record for each customer.

SELECT * FROM ( SELECT Order.OrdDate, Orders.OrderNo, Orders.Amount, Customer.Name,ROW_NUMBER() OVER(PARTITION BY Customer.Name ORDER BY Order.OrdDate DESC) AS RowNum FROM Orders Orders
INNER JOIN Customer Customer ON Orders.CustomerID=Customer.ID
) X
WHERE
X.RowNum= 1

By changing the final WHERE clause you can also do things like select the last 3 orders for each customer:

X.RowNum <= 3

And the OVER() can also be used without the row_number() to create running totals in your SQL results. For instance this expression would create a running sum of order amounts for each customer:

sum(orders.amount) OVER( PARTITION BY Customer.Name
ORDER BY Order.OrdDate DESC) AS RunningAmt




Using an asterisk for ALL in a parameter

Monday 17 December 2018 @ 11:43 pm

I recently wrote about using ALL when working with parameter fields. After my newsletter went out I got a comment from Bruce Ferguson of Crystal Kiwi in New Zealand (thanks Bruce!). He mentioned that he prefers to use an asterisk instead of the word ALL. This sorts to the top of the list automatically, and us old-timers are used to thinking of the asterisk as a wildcard.  It also doesn’t get confused with similar values, like the state abbreviation “AL”

This reminded me of a lesson from my advanced class. We create a string parameter and write a selection formula like this:

{Customer.PostalCode} like {?Zip}

This can be used three ways by the user.

1) If they enter the full code like 20176 they will get exact matches.
2) They could also do a partial match like 601*. This would give them all postal codes that started with 601. They could enter any number of characters to get a broader or narrower group.
3) If they enter just an asterisk, they would get ALL values, with one exception. They would get records that have a blank postal code, but they would NOT get records that have a NULL postal code.

So, if you want to use LIKE and still have the asterisk return all values, including NULL values, you would need to do something like this:

if {?zip} = "*"
then True
else {Customer.PostalCode} like {?Zip}




SQL to return the last record (SQL Server)

Friday 7 December 2018 @ 10:23 pm

A few years ago I wrote a post that showed a more efficient way to find a ‘last’ record in a SQL command, while pulling several values from that record.

The example I used then was written in the SQL Syntax for MS Access, but the same method can be used in other flavors of SQL. The main difference is the syntax for converting the date to a string. Since I just had to look up that syntax for MS SQL Server I decided to post this here so I can find it easily next time.  Here is a brief recap of what it does:

In SQL it is very easy to add a GROUP BY clause to a query and then calculate the Min() or Max() date for that group. For instance the last order date for a customer. What is not so simple is to return other fields from each last order record, like the Order Number and Amount. The typical solution is to find the maximum in initial query, and then link that to another query that matches that Max() value back to the matching record as an inner join. But this requires at least to queries, and can get complicated if the GROUP BY field and the Max() field are in separate tables.

I find that it is simpler and more efficient to do the Max() on a combined expression that includes all the fields you want. This works as long as you start the expression with the date converted to a string in “yyyymmdd” format. This format ensures that the Max() of the combined expression will be the date and values from the last record.

Take a simple example. We need to write SQL to return each customer’s last order. And from that order you also want to return the customer name, order date, order number and amount. The SQL would look like this:

SELECT
Customer.ID,
max(
CONVERT(varchar(16), Order.OrdDate, 121) + '*' +
Orders.OrderNo + '*' +
Orders.Amount + '*' +
Customer.Name
) as MaxSTring
FROM Orders Orders INNER JOIN Customer Customer ON Orders.CustomerID=Customer.ID
WHERE (Orders.OrdDate>={ts '2018-11-01 00:00:00'} AND Orders.OrdDate<{ts '2018-12-01 00:00:00'})
GROUP BY Customer.ID

This returns one row per customer and the row might look something like this:

20180630*12345*250.87*Joe Smith

You can then write a formula in Crystal to split the string back into pieces. For instance the Customer Name formula would look like this:

Split ({Command.MaxString}, '*') [4]

In English this says, split the MaxString into a list (array) based on the asterisks. Take the 4th element.

Some of you might be wondering why we don’t just do this in the report.  You have a point since this is simple in Crystal:

Group by customer, sort by date, hide the Details and Group Header. Show all the fields on the Group Footer.

This works great, but is not very efficient if you have a large volume of data, because it requires Crystal to read all the details and display the last one. The SQL version above would only return one record per customer to the report.




Jeff-Net

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