Αποτελέσματα Αναζήτησης
15 Μαρ 2012 · select COALESCE(type_id, 'Unknown') AS type_id, name from test_table group by COALESCE(type_id, 'Unknown'), name; COALESCE is more efficient than NVL as it only evaluates the second argument if the first is NULL whereas NVL evaluates both arguments every time. Hope it helps...
1 Ιουν 2023 · Oracle DECODE Function with NULL Values. As I mentioned above, the Oracle DECODE function is an exception to other functions in how it handles NULL values. It treats a NULL expression and NULL search as equal (so NULL == NULL). So, this example will return 1: SELECT DECODE(NULL, NULL, 1, 0) FROM DUAL;
Oracle DECODE() function and NULL. NULL cannot be compared to anything even NULL. However, DECODE() function treats two null values are being equal. The following statement returns the string Equal: SELECT DECODE (NULL, NULL, 'Equal', 'Not equal') FROM dual; Code language: SQL (Structured Query Language) (sql)
The Oracle/PLSQL DECODE function has the functionality of an IF-THEN-ELSE statement. Syntax. The syntax for the DECODE function in Oracle/PLSQL is: DECODE( expression , search , result [, search , result]... [, default] ) Parameters or Arguments. expression. The value to compare.
If the first result has the data type CHAR or if the first result is null, then Oracle converts the return value to the data type VARCHAR2. In a DECODE function, Oracle considers two nulls to be equivalent. If expr is null, then Oracle returns the result of the first search that is also null.
The DECODE function is not specifically for handling null values, but it can be used in a similar way to the NVL function, as shown by the following example. SQL> SELECT id, DECODE(col1, NULL, 'ZERO', col1) AS output FROM null_test_tab ORDER BY id; ID OUTPUT ----- ----- 1 ONE 2 ZERO 3 ZERO 4 ZERO 4 rows selected. SQL> NVL2
14 Ιουν 2007 · How can I check if a field is not null in a decode statement. select decode(field1, not null, 'Y', 'N')
