Question

我正在尝试向正在开发的查询中添加Case语句。在其中一个连接上，我需要添加要连接的字段的条件。 1.如果field1不为null，请使用它 2.否则，如果不为null，则使用field2 3.否则使用fallbackField。

我有一个仅使用sql的有效查询。但是希望将其转换。我也有一个多重联接设置（只需要一个条件）

有效的原始sql


SELECT * 
FROM   customers c 
       INNER JOIN member_customers mc 
               ON c.id = mc.customer_id 
       INNER JOIN enums e 
               ON CASE 
                    WHEN e.source_id IS NOT NULL 
                         AND mc.id = e.source_id THEN 1 
                    WHEN e.org_id IS NOT NULL 
                         AND c.org_id = e.org_id THEN 1 
                    ELSE e.enum_name = 'Sold' 
                  END = 1 
       INNER JOIN enum_values ev 
               ON e.id = ev.enum_id 
                  AND mc.state = ev.enum_value 
WHERE  mc.user_id = 999
GROUP  BY c.NAME

我到目前为止的蛋糕转换

        $query = $this->Customers->MemberCustomers->find('all')
            ->contain(['Customers'])
            ->join([
                'c' => [
                    'table' => 'customers',
                    'type' => 'LEFT',
                    'conditions' => 'c.id = MemberCustomers.customer_id'
                ],
                'e' => [
                    'table' => 'enums',
                    'type' => 'LEFT',
                    'conditions' => '//where the conditions need to be'
                ],
                'ev' => [
                    'table' => 'enum_values',
                    'type' => 'LEFT',
                    'conditions' => 'e.id = ev.enum_id AND MemberCustomers.state = ev.enum_value'
                ]
            ])

Answer 1

我找到了解决这个问题的方法。

$caseConditions = $query->newExpr()->addCase([
$query->newExpr()->add(['e.source_id IS  NULL AND MemberCustomers.id = e.source_id']),
$query->newExpr()->add(['e.source_id IS  NULL AND MemberCredentials.id = e.source_id'])
...
])

比条件部分

'conditions' => $caseConditions

Answer 2

'e' => [
    'table' => 'enums',
    'type' => 'LEFT',
    'conditions' => 
        '(CASE WHEN e.source_id IS NOT NULL
        AND mc.id = e.source_id THEN 1
        WHEN e.org_id IS NOT NULL 
        AND c.org_id = e.org_id THEN 1 
        ELSE e.enum_name = 'Sold' 
        END) = 1'
]

将CASE添加到Cake查询联接中

2 个答案: