24
Wed, Jul
0 New Articles

TechTip: TO_CHAR: Formatting Dates in SQL

SQL
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

 

ANSI SQL is extremely limited when it comes to date formatting, but DB2 provides a powerful extension that alleviates that problem.

 

SQL is becoming ever more popular in most IBM i shops, and for good reason: it makes it very easy to do things that are perhaps not so easy in RPG. SQL also provides a standard interface to various tools that aren't specific to the platform, primarily through ODBC and JDBC. However, SQL isn't a silver bullet. There are things that are easier and faster in RPG, and some things that are nearly impossible to do in SQL.

Date Formatting

For the longest time, date formatting has been one of the biggest shortcomings of SQL. For whatever reason, ANSI SQL still has no standard function for formatting dates. In most cases, you end up with something along the lines of this:

 

SELECT ORDNUM,

SUBSTR(DIGITS(ORDDAT,5,2)) || '/' ||

SUBSTR(DIGITS(ORDDAT,7,2)) || '/' ||

SUBSTR(DIGITS(ORDDAT,3,2))) AS DATMDY

FROM ORDERS

 

And this is a fairly easy case, where the date is already formatted into a CCYYMMDD field. Not particularly intuitive and definitely a whole lot of typing, which in turn means a whole lot of opportunity for typos. That propensity for error increases as you add more date fields.

What Are the Alternatives?

One way to address the problem is to write your own user-defined function (UDF). I actually did that by extending Alan Campin's excellent iDate function, available from Think400. The standard iDate utility converts non-date data into variables of the actual SQL date type. This is the converse of today's topic, but it's definitely a tool you're going to want to have in your arsenal. I just added some routines written in RPG to convert date variables to numbers (for legacy databases) and strings (for reports).

 

The other option is to rely on the vendor-specific extensions, if any. Microsoft SQL Server, for example, provides a very specific conversion function not surprisingly named CONVERT. This function takes a date and returns a variable of the selected type. For example:

 

CONVERT (VARCHAR, myDate, 101)


This returns the date in mm/dd/yyyy format. CONVERT can also be used to convert a string into a date variable using the same style values. There are about 20 different style values, and about a dozen of those have two-digit year variants.

 

The problem, of course, is that this function isn't available on DB2. In fact, prior to DB2 8.5 or so, you had exactly one possibility: you could convert a timestamp to YYYY-DD-MM HH(24):MI:SS using the function VARCHAR_FORMAT. That's the only supported format. If you went to the InfoCenter documentation on the function you saw a section that said "Valid format strings are:" and then that one format string. Click here if you think I'm kidding.

 

This is what we had on the IBM i up until V5R4. We had no other options (although I did manage to get it to work with YYYY-MM-DD). However, in DB2 9.5 (and in DB2 for the IBM i v6.1), IBM added a whole raft of other conversion options. Check out the InfoCenter page for more information, but generally speaking just about any conversion you can think of is now available. This includes standard values such as two-digit months and hours in either 12- or 24-hour format, advanced values such as either full or partial month names (as an example, although the page doesn't show it, MON in either upper, lower, or title case will return the abbreviated month name in the corresponding case), and even obscure options such as ISO or standard week number, or quarter (1-4).

 

So now you can get rid of your strange and twisted substring notations and come into the wonderful world of real date formats:

 

SELECT ITEMNO, TO_CHAR(LASTMNT, 'DD-Mon-YYYY') FROM ITMMST

 

XX123JUP08   05-Feb-2012

 

Notice that I used TO_CHAR instead of VARCHAR_FORMAT. TO_CHAR is a great synonym for those of us who are typing challenged. Also, TO_CHAR requires real date-type dates, but if your database isn't yet upgraded to all date data types, you can still use iDate to convert them for you. And that's a great discussion for another day. Have fun!

 

 

Joe Pluta

Joe Pluta is the founder and chief architect of Pluta Brothers Design, Inc. He has been extending the IBM midrange since the days of the IBM System/3. Joe uses WebSphere extensively, especially as the base for PSC/400, the only product that can move your legacy systems to the Web using simple green-screen commands. He has written several books, including Developing Web 2.0 Applications with EGL for IBM i, E-Deployment: The Fastest Path to the Web, Eclipse: Step by Step, and WDSC: Step by Step. Joe performs onsite mentoring and speaks at user groups around the country. You can reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..


MC Press books written by Joe Pluta available now on the MC Press Bookstore.

Developing Web 2.0 Applications with EGL for IBM i Developing Web 2.0 Applications with EGL for IBM i
Joe Pluta introduces you to EGL Rich UI and IBM’s Rational Developer for the IBM i platform.
List Price $39.95

Now On Sale

WDSC: Step by Step WDSC: Step by Step
Discover incredibly powerful WDSC with this easy-to-understand yet thorough introduction.
List Price $74.95

Now On Sale

Eclipse: Step by Step Eclipse: Step by Step
Quickly get up to speed and productivity using Eclipse.
List Price $59.00

Now On Sale

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: