The SQL statement above would return 'n/a' if the supplier_city field contained a null value. Otherwise, it would return the 'Completed'. Another example using the NVL2 function in Oracle/PLSQL is: select supplier_id, NVL2(supplier_desc, supplier_name, supplier_name2) from suppliers; This SQL statement would return thesupplier_name2field if thesupplier_d...
nvl2(first_name, first_name ||' '|| last_name,'Not assigned') salesmanFROMordersLEFTJOINemployeesONemployee_id = salesman_idWHEREextract(YEARFROMorder_date) =2017ORDERBYorder_dateDESC;Code language:SQL (Structured Query Language)(sql) In this example, theNVL2()function checks if the first na...
DECODE functioncan be used in a similar way to NVL2 when theexpressionandsearchparameters are both null. The difference is that for DECODE, the return will have both the value and the data type of theresultparameter. In contrast, for NVL2, the return will have the value of either thenot_...
内部函数 1、内部合计函数 1）COUNT（*） 返回行数 2）COUNT（DISTINCT...
SQL Server does not support the ZEROIFNULL function. However, its functionality can be easily replaced in several ways. For example: DECLARE @val INT=10 --1 SELECT CASE WHEN @val IS NULL THEN 0 ELSE @val END AS Val --2 SELECT IIF( @val IS NOT NULL, @val, 0 ) AS Val ...