DR Report Development
Strategies using Transact-SQL
By Acmeware, Inc.
Glen R. D’Abate - President
Introduction
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Acmeware
Course Objectives
Review Participants Experience
Course Summary
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T-SQL Overview
T-SQL Basics
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SELECT Statement
TABLE JOIN Strategies
WHERE Filters & Using T-SQL Functions
GROUP BY & HAVING
ORDER BY & UNION
Advanced T-SQL Topics:
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Sub-Queries, Temp Tables, & Embedded Queries
Parameters
Cursors
Indexes
Lots of Examples
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Examples are derived from real
problems requested by our clients
Most statements have be drastically
simplified to demonstrate the topic of
discussion
We will provide example code via email if you have an interest in
receiving these
Why use T-SQL?
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Server side-processing
Modular Solutions Construction
T-SQL Extends ANSI SQL
Access to SQL Server Function Set
Access to SQL Server System Stored
Procedure & Extended Stored
Procedures
What is Created with T-SQL
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Query Analyzer Ad-hoc Queries
SQL Server Stored Procedures
SQL Server Views
Application Specific Queries that passthrough (e.g., Access, SRS, etc.)
Where to use T-SQL Code
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Query Analyzer
Microsoft Access
Visual Basic / C# and .ASP
Crystal Reports / Crystal Enterprise
Cognos / Actuate / Business Objects
T-SQL Basics
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SELECT, DISTINCT, Aggregate Functions
FROM, JOIN, ON
WHERE
GROUP BY
HAVING
ORDER BY
UNION
SELECT / DISTINCT
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The SELECT Statement identifies fields
or columns of data that will be returned
in the Result Set
Column values may be
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An explicit value from a data source
An aggregate of a data value
A derived value from a T-SQL expression,
A literal value
Result Set
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A set of Records (or Rows) returned as a
result of processing the T-SQL code.
Each and every record has a value or a
NULL for each column or field defined in
the T-SQL statement.
Example Result Set
Result Columns
Result Records
NULL values: NULL
implies “unknown”
SELECT Statement
About as simple as it
gets. Asterisk means
return all columns
SELECT with Aggregate
Counts all BillingIDs in
table
Total all ChargeTotals
in table
Totals charge
Amounts for a given
SourceID & VisitID
SELECT with Expression
Expression with string
manipulation function
IsNull() function is used
often with DR data
Note missing column name
SELECT with Literal
Literal expressions are
common when the UNION
operator is used as a
method to indicate which
result set of the UNION a
record was derived from.
Note literal expressions are
omitted from the Group By
statements
SELECT Distinct
Distinct means distinct
record in the Recordset,
not distinct column unless
the Recordset has only one
column.
SELECT Statement - TOP N
TOP N limits the result set
to the first N records. This
is used most often with the
ORDER BY clause, or
when trying to get a quick
snapshot of data.
ANSI SQL Syntax
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SELECT, DISTINCT, Aggregate Functions
FROM, JOIN, ON
WHERE
GROUP BY
HAVING
ORDER BY
UNION
DR Table Joining Strategies
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Primary Keys are defined in all tables and table data is
sorted by the MEDITECH defined Primary Key
Clustered Index
The SourceID is a DR-only construct defined to allow
multi-database MT application implementations to
exist in the same DR table. Also, multiple MT
universe implementation can feed a single DR using
SourceID to delineate data. SourceID is in virtually all
DR tables.
Foreign Keys are only identified by MEDITECH DR
naming convention (i.e., end in ID). No declared
Foreign Key relationships exist)
The hierarchy that existed in the NPR data structures
are typically reconstructed through PK to PK table
links within a module
DR Table Joining Issues
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PatientID defines Patient level data (i.e., Medical
Record Unit Number externally)
VisitID defines Visit level data (i.e., AccountNumber)
VisitID joins provides cross modules linkage and
should be used for inter-module table joins
Most modules have internal IDs for linking within
(e.g., ABS - AbstractID; B/AR - BillingID; LAB SpecimenID) which should be used for intra-module
table linking
More DR Joining Factors
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SourceID should typically be included in
DR Table Joins
Outer Joins are common where Nulls may
exist in a Table (e.g.., looking for
“Attending Provider” if he/she exists.)
Unit Number or PatientID Joins can be
used to compare a patient’s visits with
other visits by the same patient (i.e.,
revisits within 72 hours)
Five Common DR Join
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Intra-Module Join
Module - Dictionary Join
Inter-Module Join
Table Self-Join
Outer Join (Left or Right)
Intra Module Join
Example: Create a JOIN that includes
general Billing / Accounts Receivable
(B/AR) information (i.e., from NPR main
segment) and includes the Patient
demographic as well as financial
information associated with a visit.
B/AR Intra-Module Join
BarVisitFinancialData is at the
same segment level of the NPR
structural as BarVisits (I.e., both
are BAR.PAT
Always use
SourceID within
a module
Note table naming nomenclature. Main segment tables
are plural (e.g., BarVisits). Subordinate NPR tables
have the same prefix with the addition of the Segment
name (e.g., BarVisitFinancialData, BarVisitProviders)
Module Join to a Dictionary
Example: Create a JOIN that includes
B/AR Charge detail information as well
as detail about the specific charge
Transactions. This requires the use of
the MEDITECH B/AR Procedure
dictionary, which is named
‘DBarProcedures’ in the DR.
B/AR Module to
B/AR Dictionary Join
Often times, the fact table FK will be
named more specific than the
corresponding PK dictionary table (e.g.,
TransactionProcedureID,
OrderingProviderID, etc.)
Dictionaries in the DR all begin with ‘D’module (e.g.,
DMisProviders, DBarProcedures, DLabTests, etc.)
B/AR Module to
MIS Dictionary Join
When linking to MIS dictionaries, the
SourceID may, or may not be appropriate.
This depends on whether you are using a
multi-database module (e.g., B/AR) and
multiple databases exist. Also, we have
seen the LAB module set up with different
SourceIDs
Inter Module Join
Example: Create a JOIN that includes Visit
Demographic information with Laboratory
Test results.
Inter-Module with Lab data
SourceID should be used if
it can be used
VisitID is key for cross
module joins
Inter-Module with MRI
Demo-Recall data
Patient ID is used for MR
queries.
Table Self Join
Example: This type of query can be used to
look at activity within a visit in the
AdmVisitEvents table. Create a JOIN that
finds patient transferred from a location,
to a second location, then back to the
original location within within 4 hours of
being transferred out of that unit.
Self Join using Visit Events
This will identify the same
transfer multiple times if
multiple transfers occur
within a 4 hour window
Outer Join
Example: Create a JOIN that identifies a
patient’s top two ICD-9 procedures and
top two diagnosis, regardless of whether
or not they exist
Outer Join with ICD-9s &
Diagnoses
Alias the ICD-9 and
Diagnosis tables twice in
order to identify primary
and secondary
occurrences, if they exist
Outer Join (Example 2)
Example: Create a JOIN that identifies all
visits (by discharge or service date) that
have occurred more than two months
ago, and do not have a Bill generated
Outer Join Finding Missing Bills
Filter for missing BarBills
entries
ANSI SQL Syntax
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SELECT, DISTINCT, Aggregate Functions
FROM, JOIN, ON
WHERE
GROUP BY
HAVING
ORDER BY
UNION
The WHERE Clause
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Specifies a filter condition to restrict the
rows returned to the record set
The WHERE expression simply evaluates
a Boolean (True or False) value that
determines if the record, as identified in
the JOIN process) is to be returned
May use operators, functions, and subqueries in the expression
WHERE Clause: Find all current
inpatients and list the patient’s
admission date, current location –
defined as room location, room, and bed
Patients who have been
admitted, but not yet
discharged are considered
current inpatients
WHERE Clause: Identify the Reason
employees have been terminated in less
than one year for specific job codes
This example uses the
function DateDiff() as well
as the IN function.
WHERE Clause: Find patients with first
name beginning with ‘J’, specific Zip
Codes and Diagnoses
IsNumeric() function can be used to verify a
value i numeric before performing a
mathematical function…this is VERY useful
when working with DR data
Like function allows for
pattern matching in the
WHERE filter
WHERE Clause: String manipulation
functions to clean up Name conversion
problem
Left(), Right(), and SubString() functions allow
for string extraction from within a string
Identifying a strings within
a string can be performed
using the Charindex()
function
ANSI SQL Syntax
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SELECT, DISTINCT, Aggregate Functions
FROM, JOIN, ON
WHERE
GROUP BY
HAVING
ORDER BY
UNION
Aggregate Functions
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T-SQL Aggregate functions are used to
summarized data values by:
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Count(), Count(Distinct)
Avg(), Avg(Distinct)
Sum(), Sum (Distinct)
Max() & Min()
HAVING Statement allows filtering of
aggregate values
Aggregate Example: Census by
Location and Date
The Count() aggregate counts
all non-NULL entries. If Nulls
are encountered, a warning is
displayed.
The AdmNursingCensus
table captures the census
at midnight run. Each
inpatient is assigned to the
current location in which
they reside.
Aggregate Example: Create a T-SQL
statement that identifies by Final DRG
the Average Length-of-Stay (as defined
by Medicare), and number of Medications
a patient received. Only consider patient
visits in 2004 and only include DRG
results if more than 2 visits occurred with
the DRG.
Medicare defines LOS as 1 for a
single days stay, and the
number of midnights for a
multiple day stay
The statement counts the
unique DrugIDs that were given
at anytime during a stay.
The HAVING filter removes
records from the result set
AFTER the aggregation has
been performed. We only
consider DRS when more than
2 visits with the DRG have
occurred.
Aggregate Example: Identify the Average
Charges associated with a patient visit by
Attending Provider for a given Major
Diagnosis Group and also show the
number of cases that were used to
compute this average?
Diagnosis codes are sometimes
entered with a leading
character. In this case, remove
the leading character.
Because a single visit may have
multiple Diagnoses, we must
count DISTINCT VisitIDs
Charge Total is available from
BarVisitFinancialData. It could
also be derived from
BarChargeTransactions
Each visit should only have one
‘Attending’ Provider. You may
need to verify this.
Only Final Bill (FB) accounts are
considered and only those with a
diagnosis that contains a “.”
GROUP BY statement must
match the non-Aggregate
columns in the SELECT
statement
ANSI SQL Syntax
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SELECT, DISTINCT, Aggregate Functions
FROM, JOIN, ON
WHERE
GROUP BY
HAVING
ORDER BY
UNION
ORDER BY / UNION
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Order By allows sorting of the result set
The result set sorting can be specified by
column name, column alias, an expression, or
by position in result set
Union allows two result sets to be concatenated
and returned as a single result set.
All columns must be of the same datatype for
UNION to function
By default, UNION is UNION Distinct, unless
UNION ALL is specified
ORDER BY Example: Create a T-SQL
Statement that lists all Inpatient
Admissions that occurred in the March
2005 and sort the output by Admitting
Priority, then by Admitting date and
time.
Sorts first by Admitting Priority,
then by AdmitDateTime
Default Sort is ASC (ascending),
Optionally can sort by DESC
(descending order)
Note, a item need not be in the select statement
to be used in the ORDER BY. However, if a
aggregate exists in the SELECT, then the item
being sorted must be in the SELECT or
GROUP BY statement
ORDER BY Example: Create a T-SQL
statement that counts the number of
Laboratory specimens per hour-of-day
that were completed in 2005.
Only completed specimens that
occurred this year
This example sorts based on an
expression (i.e., the
computation of the hour of a day
a specimen was received)
This data can be used to
schedule phlebotomist more
accurately
ORDER BY Example: Create a T-SQL
Statement that provides a count of
outpatient visits after 1/1/2004 by
calendar month and sorts the output
by month & year properly.
Solution 1: Use Year() and Month()
functions and then sort the output using a
concatenated string value representing
the month and year.
For this strategy to function properly, the
sort value must be in the SELECT or
GROUP BY statement.
This solution works well when parameters
are passed (e.g., from Access Form or
Crystal Parameter) and returns integer
values for FY and FM.
Solution 2: This returns the first day of the
month to represent all admissions in a
given month. This returns a datetime
datatype in the Month column
Transaction ServiceDateTime is converted to
the first day of the month using a
combination of Convert first to a string value,
then back to a datetime value.
UNION Example: Create a T-SQL Query
that in a single result set, returns all
Charge, Receipt, Adjustment, and
Refund Transactions in a single result
sent.
Charges
Receipts, Adjustments,
Refunds, etc.
BarChargeTransactions and
BarCollectionTransactions are similar
tables with the former having charge data
and the latter having receipt, adjustment,
refund, and other data. When brining this
data together into a result set, a UNION
operator is often used.
Note that it is possible to achieve the
same output using a FULL OUTER JOIN
and recognizing that the TransactionID is
unique across the two tables, but we find
this approach to be significant less
efficient
Advanced Concepts: SubQueries, #Temp Tables,
Embedded Queries, Cursors,
Parameters & Indexes
Non-Correlated Sub-Queries
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Non-Correlated Sub-Queries in the WHERE
clause typically can also be written using a
JOIN
Non-Correlated Sub-Queries can also be in the
SELECT statement
Non-Correlated Sub-Query Example:
Create a T-SQL query that identifies all patients
that have ever been in a room where any
patient has ever been identified with the
Microbiology Organism of MRSA?
Finds the home phone of the patient who
has been in the location of interest
This essentially creates a list of all
locations where an MRSA infection has
been isolated.
Sub-Queries are enclosed in parenthesis
Correlated Sub-Queries
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Correlated Sub-Queries use values in the
“outer query” to derive the vales in the
“inner sub-query.”
Example: Create a T-SQL Query that
shows Charge Transaction procedures
and the appropriate Revenue Value Unit
(RVU) that is associated with the charge
transaction.
Wherever an EffectiveDateTime is
in use, the code below is
generally required to tie the date
of the activity to the correct
EffectiveDateTime.
When an aggregate is used in a
sub-query, it is not possible to
emulate the same logic with a
JOIN clause.
Note effective date is always
prior to ServiceDateTime
Using Temporary Tables
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Temporary tables are extremely useful when a
problem cannot be solved using a single query
Temporary tables are efficient
Temporary tables can be session specific (#T),
or can persist while in use by multiple sessions
(##T)
Temporary tables can be used to break down
complex queries into simpler, modular
components
Note, this is the same T-SQL
statement we saw earlier in the
UNION section. It brings charges
together with receipts, adjustments,
refunds, etc., but now loads this into
a #temp table. The data is then be
aggregated by visit
The data is then be
aggregated by
AccountNumber (visit)
using the temp table, and
displayed in separate result
set columns using the
CASE statement
Embedded Query
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Because a T-SQL statement returns a
result set, and a result set is essentially
structured the same as a table, the TSQL statement itself can be used in the
FROM Clause of another query.
We do not often use this method as it
often more difficult to support than
using #Temp tables to accomplish the
same result.
Embedded sub-query
returns receipts and
expected reimbursement
by FC and insurance and
insurance order.
This T-SQL statement, which you may have
already developed, can be easily used as
an embedded sub-query to solve the
problem of identifying total outstanding
balances by Financial Class.
T-SQL Cursors
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A SELECT statement returns a complete result set
containing all the rows that meet the qualifications
in the SELECT statement.
Solutions that require a need to process a result set
one row (or block of rows) at a time can utilize
Cursors.
A cursor typically loops through a result set and
performs an operation (i.e., Update, Insert, etc.) on
a table based on values in the records being
processed by the cursor
Cursors tend to be overused (especially by
programmers and NPR RWers as an easy solution
Cursors are very inefficient and we avoid using
them unless absolutely necessary
Example: We need to create a T-SQL
statement that identifies the TOP 5 DRGs
utilized by Admitting Provider (using the
AbstractProvider table). That is, for any given
provider, we want to list that provider top 5
DRSs. This requires that the SELECT TOP 5
clause be repeated for each Admitting
Provider. The only way to solve this is
through the use of a cursor.
Create a temporary table to receive the results
Cursor Query identifies all Admitting Providers
FETCH_STATUS determines when the cursor
has completed a pass through the result set
Results are returned by
SELECTing on the
temp table
Cursor value (@Provider) is
used in filter to get TOP 5
DRGs by Provider
FETCH NEXT retrieves the
nest record in the result set
Stored Procedure Parameters
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The vast majority of T-SQL statements
we construct are within entered within
Stored Procedures and contain
parameters.
Parameters allow the user running an
Access. Crystal, or SRS report to
configure the output based on input
constraints.
Highlighting code allows you to
execute specific code in QA
Stored Procedure Parameters
Syntax for modifying a SP.
CREATE is used to create a SP
Parameters must have
datatype defined
Parameters can be
used in any part of the
T-SQL statement
where the datatype of
the parameter allows
Using Table Indexes
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Table Indexes can decrease T-SQL statement
processing times
Indexes trade off space and table update
efficiency with query performance
Build indexes on Joined and/or Filtered columns
Covered Indexes take more space, but can insure
fast response time
A rule of thumb is that the SQL Optimizer will
filtered results using an index if the result set is
reduced by a factor of 6 to 20
Query Analyzer can be used to check if an index
is put to use
Manage Index options (from Table context
menu in Enterprise Manager) allows you to
add, modify, or remove indexes
IX_ColumnName(s) is a
common nomenclature for
naming indexes
In general, when creating
DR based indexes, you will
not check any of these
options.
Note, ServiceDateTime
index is NOT used, even
though a filter on this
columns is specified?
Index SCANs require each row
to be examined. Index SEEKs
allow the optimizer to go
directly to the row-of-interest
Estimated Execution Plan
in Query Analyzer allows
you to see how the SQL
Optimizer will arrive at a
result set solution.
MEDITECH supplies a
clustered index on every
table which determines the
default sort order of data in
the table
Now the ServiceDateTime
index IS used with virtually
the same Query?
Index SEEK is very efficient
IX_ServiceDateTime is now
used by optimizer, however a
Bookmark Lookup is also
required to find the Act # and
Name
System SPs & Extended SPs
This SP uses XP_SendMail
to notify individuals that an
employee was terminated
and asks them to perform
certain tasks based on this
information
Email address list is derived from another T-SQL statement