DB2 data manipulation

developerWorks®ibm.com/developerWorksSELECT UNIT_PRICE, CURRENCY('UK',UNIT_PRICE) FROM PRODUCT WHERE PRODUCT_ID = ?FENCED and NOT-FENCED modesYou can create functions in C/C++, the Java language, or OLE. A function can run inFENCED or NOT-FENCED modes. You should develop a function in FENCED modebefore migrating to NOT-FENCED mode. A NOT-FENCED process is faster, as it usesDB2 agent memory, whereas a FENCED process runs in its own db2udf process. AFENCED process uses shared memory to communicate with the calling agent.FENCED functions are stored in sqllib/function and unfenced functions arestored in sqllib/unfenced.DB2-supplied SQL functionsNow look at examples of a few SQL functions. The first example selects the title andprice for all books in a table. If the price for a given title is NULL, the price shown is0.00SELECT TITLE, COALESCE(PRICE, 0.00) AS PRICEFROM TITLES;Next, you'll see an example that returns a company name and the number ofcharacters in that company's name:SELECT COMPANYNAME, LENGTH(COMPANYNAME)FROM CUSTOMERSNow see how you can return the five right-most characters of each author's firstname:SELECT RIGHT(AU_FNAME, 5)FROM AUTHORSThis next example, using the project table, sets the host variable AVERAGE(decimal(5,2)) to the average staffing level (PRSTAFF) of projects in thedepartment (DEPTNO) called D11.SELECT AVG(PRSTAFF)INTO :AVERAGEFROM PROJECTWHERE DEPTNO = 'D11'There are many other SQL functions defined in the DB2 SQL Reference manual.You can always write your own SQL function if DB2 does not provide one.DB2 data manipulationPage 8 of 25© Copyright IBM Corporation 1994, 2007. All rights reserved.