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29 Δεκ 2014 · TO_DATE with proper format model should do the trick. Let's stick to a format model first. SQL> alter session set nls_date_format='dd/mm/yyyy hh24:mi:ss'; Session altered. Now, let's use TO_DATE to explicitly convert the string literal to date.
For example, you can use the CASE expression in statements such as SELECT, UPDATE, or DELETE, and in clauses like SELECT, WHERE, HAVING, and ORDDER BY. Oracle CASE expression has two formats: the simple CASE expression and the searched CASE expression. Both formats support an optional ELSE clause.
15 Μαρ 2021 · You can use a SCALAR SUBQUERY - a query that returns zero or one rows with exactly one column. So this will work: 1* select case when dummy = 'X' then (select count(*) from all_users) else (select count(*) from dual) end cnt from dual ops$tkyte%ORA10GR2> / CNT ----- 46
In a simple CASE expression, Oracle Database searches for the first WHEN... THEN pair for which expr is equal to comparison_expr and returns return_expr. If none of the WHEN... THEN pairs meet this condition, and an ELSE clause exists, then Oracle returns else_expr. Otherwise, Oracle returns null.
Is there a "better" way to rewrite a SELECT clause where multiple columns use the same CASE WHEN conditions so that the conditions are only checked once? See the example below.
7 Δεκ 2023 · How to use CASE for IF-THEN logic in SQL SELECT. If you want to see the grade for each exam, select the case expression like a regular column: It’s a good idea to give the expression an alias. This is particularly important if the case is in a subquery.
SELECT ename, empno, deptno, (CASE deptno WHEN 10 THEN 'Accounting' WHEN 20 THEN 'Research' WHEN 30 THEN 'Sales' WHEN 40 THEN 'Operations' ELSE 'Unknown' END) department FROM emp ORDER BY ename; The value match CASE expression is also supported in PL/SQL. The example below uses it in an assignment.
