sql - 如何在Oracle的where子句中使用IF THEN ELSE语句？

Question

我很感兴趣的是如何在 Oracle 的 where 子句中使用 if-then-else 语句或任何控制结构。我想用作:

• 当pcustomer_id IS NULL时，WHERE c.customer_id IS NULL
• 当pcustomer_id IS NOT NULL时，则c.customer_id = pcustomer_id。

我该怎么做？

SELECT *
  FROM customer_inf c
 WHERE 
IF
 pcustomer_id IS NULL THEN ( c.customer_id IS NULL ) 
    ELSE (c.customer_id = pcustomer_id) END IF;

Answer 1

您需要捆绑它们

where (
(pcustomer_id is null 
    and c.customer_id is null)
or 
(pcustomer_id is not null 
    and c.customer_id = pcustomer_id)
)