Ok, heres a sample conversion that works for clob i just came up with. Plsql is a combination of sql along with the procedural features of programming languages. The sql decode function allows you to add procedure ifthenelse logic to queries. Consequently, the function never evaluates a search when a previous search is equal to expr. Developers and dbas get help from oracle experts on. Dzone database zone in oracle sql, should you use case, decode, or coalesce. Convert base64 to pdf online using a free decoding tool which allows you to decode base64 as pdf and display it directly in the browser. Since they are equal, the function returns the second argument which is the string one. Feb 19, 2015 the oracle decode function can be confusing to those who have never used it.
Decode is a function in oracle and is used to provide ifthenelse type of logic to sql. Plsql by example, fifth edition, presents the oracle plsql programming language in a unique and highly effective format. Oracle decode with multiple expressions or multiple decodes. In our example database, well work with table a, a version of our the customers. In the following example, the oracle decode function compares the first argument 1 with the second argument 1. Its similar to a case statement, but case is a statement where decode is a function.
Note that null values in decode function and case expression are handled differently. Because they are equal, the function returns the second argument which is the string one. Lets take a look at how the decode statement works. The decode function works on oracle and informix databases. Base64 encoding and decoding in oracle stack overflow. How can i do base64 encode decode a value in oracle. Dec 14, 2016 this video tutorial explains with proper example on how to write a decode statement, this video also demonstrates how the decode statement behaves on null values and implicit datatype conversion. Improving sql efficiency using case some time ago i wrote the power of decode a paper on using the decode function to improve report performance. It is automatically converted to the data type of the first search value before comparing. Decode function null issue oracle to sql server migration. Decode and case are very similar in their appearance but can produce very different results. Learn more about this function and some examples in this video.
I was aware at the time that decode was being replaced by case but wanted to make sure that the paper applied to as many oracle versions as possible. Plsql i about the tutorial plsql is a combination of sql along with the procedural features of programming languages. It challenges you to learn oracle plsql by using it rather than by simply reading about it. This oracle tutorial explains how to use the oracleplsql decode function with syntax and examples.
Although we recommend that you use the case expression rather than the decode function, where feasible we provide both decode and case versions of each example to help illustrate the differences between the two approaches. The first thing to note is that the decode function is defined in the expr section of the oracle sql language reference manual. Improving sql efficiency using case doug burns oracle and. And, of course, you will have a special link to download the pdf to your device. Apr 23, 2011 one of the readers of the blog has sent me a question regarding how to use the decode function in sql server. A decode expression uses the special decode syntax displayed in figure 112. Decode function and case statement is used to transform data values at retrieval time. The oracle functions case, decode, and coalesce all perform similar functionality. The decode expression is similar to the case expression in that it can print different results. In the following example, the oracle decode function compares the first argument with the second argument. It has been asked on multiple forums, what the equivalent of decode in sql server is.
And since decode is oracle specific, and case is ansi standard, the possibility exists that the decode function could be depreciated eliminated in a later release of oracle. In oracle, decode function is used to implement ifthenelse type of requirement. Sql server using decode in sql server sql server portal. The oracle decode statement was developed to allow us to transform data values at retrieval time. Hi all, could someone please help me in getting a query. The powerful decode function oracle sql tips, tricks and hacks. Here are the examples regarding how decode can be written in sql server. Suppose that a user wants to convert descriptive values in the. Base64 to pdf base64 decode base64 converter base64. It was developed by oracle corporation in the early 90s to enhance the capabilities of sql. Oracle pl sql tips by boobal ganesan this is an excerpt from the book advanced pl sql. Oracle started with the decode statement and later refined it in oracle9i, morphing it into the case statement.
Let us setup a simple test case with some data which we will insert into a table through sql loader. But new development has been done using case instead of decode. Select decode letters, first,1, second,2, third,3, 0 as ln from letterstable in sql server the equivalent code is case statement. Just as a grammar workbook would teach you about nouns and verbs by first. I was trying this by decode but the sum of the product was not correct. The user now enters a query with the decode function to convert the. Because the first argument equals the second one, the function returns the third. It allows you to provide a value, and then evaluate other values against it and show different results. It is very handy when it comes to search a variable and return the result based on search. Jan 18, 2012 in mssql microsoft sql server, there is no decode function, but there is a similar solution, it simply requires writing just a little more code. The solution is using a case when statement with a series of then statements to specify the desired result. Ask tom conditional where clause with decode oracle.
The oracleplsql decode function has the functionality of an ifthenelse statement. Aug 25, 2015 the powerful decode function posted on august 25, 2015 by carlos oracles decode is one of the functions i find more powerful and one that over the years i have used thousands of times to solve several different kinds of problems. Oracle sql case, oracle sql conditional expression, oracle sql decode merhaba arkadaslar bu yaz. The purpose of this chapter is to cover oracle sql basics as they relate to crystal. More keywords within the statement allow you to break up the logic, rather than using a series of parameters in a single function. You could use the decode function in a sql statement as follows. The maximum number of components in the decode function, including expr, searches, results, and default, is 255. Equivalent of oracles decode function on sqlserver sql. This video tutorial explains with proper example on how to write a decode statement, this video also demonstrates how the decode statement behaves on. In addition, you will receive some basic information about this pdf mime type, extension, size. If expr is null, then oracle returns the result of the first search that is also null.
Plsql is one of three key programming languages embedded in the oracle database, along with sql itself and java. In sql server, you can use case expression that is also supported by oracle. The following sections present a variety of examples illustrating the uses of conditional logic in sql statements. The oracle decode function allows you to add the procedural ifthenelse logic to the query. Basically, we can achieve the same in sql server using case and iif statements. The decode function offers a handy way to make data easier to analyze and more. In this example, the decode function compares the first argument one with the second argument also one. Ive implemented this to send cyrillic emails through my ms exchange server. Oracle decode function explained with examples database star. In oracle sql, should you use case, decode, or coalesce. Oracle decode and sql servers case when maverick web.
627 1136 925 294 1004 524 740 1181 1415 922 628 1514 735 959 991 42 203 212 806 612 1531 1385 408 1523 905 310 1379 1118 525 1363 678 428 1423 873 1530 1111 47 267 1058 1169 377 1200 534 817 1452 1050 568 618 888