Question

我有一个查询从两个表中获取记录。我想在where子句中使用和运算符。

这是我的代码：

SELECT sfo.customer_id, sfo.increment_id FROM sales_flat_order sfo 
INNER JOIN  marketplace_partnertype mptype ON sfo.customer_id = mptype.partner_id 
WHERE (mptype.type = 'free' AND sfo.status='complete') AND IF @mptype.type=='free' THEN ((DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 5 DAY ))ELSE (DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 3 DAY );

它显示IF @mptype.type=='free'附近的语法错误。

如果有人帮助解决这个问题，那应该是值得注意的。

Answer 1

If条件的语法是：

IF(<cond-expr>, <then-expr>, <else-expr>)

如果我们改变条件，它将是： -

AND IF (@mptype.type=='free', (DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 5 DAY )) ,(DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 3 DAY ))

查询将如下所示：

SELECT sfo.customer_id, sfo.increment_id FROM sales_flat_order sfo 
INNER JOIN  marketplace_partnertype mptype ON sfo.customer_id = mptype.partner_id 
WHERE (mptype.type = 'free' AND sfo.status='complete')AND IF (@mptype.type=='free', (DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 5 DAY )) ,(DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 3 DAY )))

Answer 2

语法不正确，您可以在where条件中使用case-when条件

SELECT sfo.customer_id, sfo.increment_id FROM sales_flat_order sfo 
INNER JOIN  marketplace_partnertype mptype ON sfo.customer_id = mptype.partner_id 
WHERE (mptype.type = 'free' AND sfo.status='complete')
and 
case 
 when @mptype.type = 'free' then  DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 5 DAY )
 else DATE( updated_at ) = DATE_SUB( CURDATE( ) , INTERVAL 3 DAY ) 
end

Answer 3

没有必要使用IF或CASE WHEN：

SELECT
  sfo.customer_id,
  sfo.increment_id
FROM
  sales_flat_order sfo INNER JOIN  marketplace_partnertype mptype
  ON sfo.customer_id = mptype.partner_id 
WHERE
  (mptype.type = 'free' AND DATE(updated_at) = DATE_SUB(CURDATE(), INTERVAL 5 DAY)
  OR (mptype.type = 'complete' AND DATE(updated_at) = DATE_SUB(CURDATE(), INTERVAL 3 DAY);

但如果您想以这种方式使用案例：

WHERE
  mptype.type IN ('free', 'complete')
  AND DATE(updated_at) = DATE_SUB(CURDATE(), INTERVAL CASE WHEN mptype.type='free' THEN 3 ELSE 5 END DAY)

如何在mysql的where子句中使用if条件

3 个答案: