Case and ComparisonA company has a High Growth SalesMan of the Year report, which analyzes, mainly through sales data, the salesmen whose sales amount exceeds 10% for three consecutive months, and demonstrates the indices such as their sales amount(Sales Amount), sales amount link relative ratio(Amount LRR), client count(Client Count), and client count link relative ratio(Client LRR). The report pattern is shown in following table:
The main data source of the report is the “monthly sales data”: sales table, which stores the monthly sales record of the salesmen, with salesman and month being the primary key. The structure is shown in the following table:
It can be seen that the calculation of the name-list of the salesmen whose sales amount exceeds 10% for three consecutive months is the most complex part of this report. As long as this name-list is calculated out, it is possible to use the reporting tool to easily present the remaining part. Let’s compare how SQL statement and esProc respectively calculate this name-list.
|1||with A AS|
|3||OVER (PARTITION BY salesMan ORDER BY month)-1 rising_range|
|7||CASE WHEN rising_range>=1.1 AND|
|8||lag(rising_range) OVER (PARTITION BY salesMan|
|9||ORDER BY month)>=1.1 AND|
|10||lag(rising_range,2) OVER (PARTITION BY salesMan|
|11||ORDER BY month)>=1.1|
|12||THEN 1 ELSE o END is_three_consecutive_month|
|14||SELECT DISTINCT salesMan FROM B WHERE is_three_consecutive_month=1|
- 1-4 lines: Use SQL-2003 window function to obtain the ”rising_range” of the monthly sales amout LRR of each salesman, where, ”lag” seeks the sales amount relative to the preceding month. Here, ”WITH” statement is used to generate an independnet sub-query.
- 5-13 lines: Continue to use window function to seek ”is_three_consecutive_month_gains”, the symbol of consecutive gains of slaesmen in the each record, where, ”rising_ranges” of the recent three months are biggern than 1.1 at the same time, and this symbol is 1. Otherwise it equals to 0, and here the technique ”case when” is used. Finally, ”WITH” statement is still used to generate independent sub-query B.
- Line 14: According to the result in the preceding two steps, seek the salesmen meeting the reporting condition, namely, the record whose “is_three_consecutive_month_gains equals 1. Here it is necessary to use “distinct” to filter duplicate salesmen.
A2: Refer to the calcualtion result of the preceding step, and select the group that meets the condition from A1. The condition comes from the last cell of A1 operation area, namely, Cell B3. Both B2 and B3 belong to A1 operation area. By writing the condition step by step in many cells, it is possible to reduce the difficulty.
B3: Conditional judgment. If the LRR of three consecutive months within the group is bigger than 1.1, then this group of data meets the condition. Here “amount [-1]” is for the data of preceding record relative to the data of the current record, amount/amount [-1] represents a LRR comparsion. The pselect() is used to obtain the serial number within the group, and whenever meeting the first piece of data within the group that meets the condition, pselect() immediately returns the serial number and stops repeated calculations.
A4: Obtain the serial number of the salesmen in A2, and this result is returned through JDBC to the reporting tool for use.
ComparisonThe method to calculate this case “stepwise” will be very clear, so it is relatively suitable for stored procedure. But report developers often cannot add stored procedure in the database at their discretions, so it is generally still necessary to use SQL statement to solve the problem. For general SQL-92 statement to solve this type of problem, it will be very troublesome. By using here the SQL-2003 standard that is not extensively used, it is possible to reduce the difficulty. Even so, it is still necessary to face large paragraphs of difficult-to-understand SQL. For common report developers, it is no doubt a huge challenge.
It is more agile and easy for esProc to solve this type of calculation. esProc provides an expression formula using grid style similar to Excel®, which naturally proceeds by steps. Cells can refer to calculation result one another, which saves the great efforts of complex nested queries as well as unnecessary and scrambled variables definition. esProc also provides functions on the calculations of mass data, such as relative position, serial number reference, and step-by-step calculation after grouping, which can greatly simplify calculation procedure.
From the above, it is obvious that esProc is better at solving the complex computation in the report.
Feature: a JDBC InterfaceesProc is a product with pure JAVA® structure and provides JDBC interface for JAVA reporting tools to conveniently call it. The structure schematic is as follows:
In the system adopting JAVA reporting tool, it is possible for esProc to conduct complex computation, multiple-datasource operation, and dirty data source collation. Then, the reporting tool can obtain the result returned from esProc via JDBC in the form of an access to the database. Finally, the reporting tool can be used to present the data.
Feature: Computational Capabilities Over-perform SQLesProc is a tool specially designed to calculate mass data, and has SQL statement and stored procedure the capability to. On the one hand, it conducts query, filter, grouping, and statistics just as SQL statement does; on the other hand, it can also conduct loop and branch judgment on analysis process just as stored procedure does.
In fact, SQL statement and stored procedure, which are also mass data calculation tools, have some obvious defects: Stepwise mechanism is incomplete, set-lization is incomplete, and there are lacks of serial number and reference. So in the report where is complex computation, designing a few lines of SQL statement tends to become very difficult, and also has very high requirement for technical capabilities of designers.
esProc overcomes the defects of SQL statement and can comfortably cope with the complex computation in the report.