![]() ,defaultreturnvalue ) with: expression is the value to evaluate comparevalue is the value that can match the evaluated value returnvalue is the value that is returned if comparevalue equals the value. Consider that we have date_of_hire column has VARCHAR datatype for this query. Syntax: decode ( expression, comparevalue, returnvalue, ,compare, returnvalue. Requirement – Getting rows from employee_details by using DECADE statement with ORDER BY clause. Scenario – Getting rows from existing table by using DECADE statement with ORDER BY clause. ![]() The query was as follows – SELECTīy executing above query we can get output like as follows - dept_id Requirement – Getting rows from employee_details by using DECADE statement. Is the registered trademark of Oracle Corporation.Scenario – Getting rows from existing table by using DECADE statement. Or have a suggestion for improving our content, we would appreciate your Strive to update our BC Oracle support information. The syntax is DECODE ( expression, search, result, search, result. All legitimate Oracle expertsĮrrata? Oracle technology is changing and we Independently investigate their credentials and experience, and not rely onĪdvertisements and self-proclaimed expertise. This book includes scripts and tools to hypercharge Oracle 11gĭocumentation was created as a support and Oracle training reference for use by ourĭBA performance tuning consulting professionals.Ĭonsidering using the services of an Oracle support expert should Oracle documentation notes the following syntax for decode:įilled with valuable information on Oracle SQL Tuning. In Oracle, DECODE function allows us to add procedural if-then-else logic to the query. search The value that is compared against expression. It is automatically converted to the data type of the first search value before comparing. , default ) Parameters or Arguments expression The value to compare. By using decode to change the ranges to a binary number, we can then use the sum built-in function to count the number of values within a specified range. Syntax The syntax for the DECODE function in Oracle/PLSQL is: DECODE ( expression, search, result, search, result. The power of these functions become apparent when combined with the decode built-in function. The case statement is an easier form of the decode statement. Oracle added the case function to SQL starting in Oracle9i to simplify this type of data transformation. Once we have converted the column to a 0-1 numeric value, we pass the entire clause to the sum function, and add-up the numbers.Īs we can see, the decode function is convoluted and hard to write. This is a very important SQL statement because it demonstrates the nesting of BIFs and the use of decode for counting values. For a definite not null value of JOB CODE, it would show constant value 'Job Assigned'. Sum(decode(book_type,'miscellaneous',1,0)) miscellaneous, Syntax: NVL2( string1, valueifNOTnull, valueifnull ) The SELECT statement below would display 'Bench' if the JOBCODE for an employee is NULL. Sum(decode(book_type,'management',1,0)) management, Sum(decode(book_type,'fiction',1,0)) fiction, Sum(decode(book_type,'computer',1,0)) computer, Initcap(substr(pub_name,1,20)) publisher_name, Here is the SQL to create this report in your pubs database: The default value tells decode what to display if a column values is not in the paired list. At the end of the decode statement we find a default value. Note that Oracle decode starts by specifying the column name, followed by set of matched-pairs of transformation values. ![]() Here is how we do this with the decode function: When we run SQL queries, we want to transform these values into North, South, East and West. For example, say we have a column named REGION, with values of N, S, W and E. The Oracle decode statement was developed to allow us to transform data values at retrieval time. Let's take a look at how the decode statement works. Oracle started with the decode statement and later refined it in Oracle9i, morphing it into the case statement. One of the most amazing features of the case the Oracle decode statements is that they allow us to create an index on data column values that do not exist in the database. The Oracle decode and case functions are used within the Oracle database to transform data values for one value to another. The most powerful of all of the BIFs are the Oracle decode and Oracle case function.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |