Question

我很有意思，我如何在Oracle中的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然后WHERE c.customer_id IS NULL
以及pcustomer_id IS NOT NULL然后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

你需要捆绑它们

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

Answer 2

使用布尔表达式：

SELECT *
FROM   customer_inf c
WHERE  ( pcustomer_id IS NULL AND c.customer_id IS NULL )
OR     ( pcustomer_id IS NOT NULL AND cc.customer_id = pcustomer_id);

Answer 3

如果我理解正确你只想在c.customer_id = pcustomer_id（包括null equity）时返回所有值。所以：

select * from customer_inf c 
where nvl(pcustomer_id,'999999999999') = nvl(c.customer_id, '999999999999');

您只需选择实际数据中不会出现的数字。

Answer 4

WHERE NVL(pcustomer_id,c.customer_id) IS NULL OR NVL2(pcustomer_id,c.customer_id,pcustomer_id)=pcustomer_id

说明：在此，在第一个NVL中，如果pcustomer_id为null，则传递c.customer_id并将检查Null 在第二个NVL2 1中，如果pcustomer_id不为null，则c.customer_id = pcustomer_id

如何在Oracle的where子句中使用IF THEN ELSE语句？

4 个答案: