根據用戶標識計算出現次數

Question

我對SQL/MySQL和Stackoverflow非常陌生，我嘗試通過iReport創建查詢（儘管我不必使用iReport）for SugarCRM CE。我需要的是創建一個報告，顯示鏈接到特定「用戶」（員工）的「推介」，「語音郵件」，「電子郵件」和「電話號碼」的數量。我現在的查詢已經建立了作品;但是它會多次運行數據，生成200多頁的報告。這是我目前使用的代碼：

SELECT 
(SELECT COUNT(*) FROM `leads` INNER JOIN `leads_cstm` ON `leads`.`id` = `leads_cstm`.`id_c` WHERE (leadtype_c = 'Referral' AND users.`id` = leads.`assigned_user_id`)), 
(SELECT COUNT(*) FROM `leads` INNER JOIN `leads_cstm` ON `leads`.`id` = `leads_cstm`.`id_c` WHERE (leadtype_c = 'VM' AND users.`id` = leads.`assigned_user_id`)), 
(SELECT COUNT(*) FROM `leads` INNER JOIN `leads_cstm` ON `leads`.`id` = `leads_cstm`.`id_c` WHERE (leadtype_c = 'Email' AND users.`id` = leads.`assigned_user_id`)), 
users.`first_name`,users.`last_name` 
FROM 
`users` users, 
`leads` leads 

我將不勝感激任何指導！

Answer 1

你想使用條件求和。下面使用MySQL的語法：

SELECT sum(leadtype_c = 'Referral') as Referrals, 
     sum(leadtype_c = 'VM') as VMs, 
     sum(leadtype_c = 'Email') as Emails, 
     users.`first_name`, users.`last_name` 
FROM users join 
    `leads` 
    on users.`id` = leads.`assigned_user_id` INNER JOIN 
    `leads_cstm` 
    ON `leads`.`id` = `leads_cstm`.`id_c` 
group by users.id; 

Answer 2

您可以使用COUNT與CASE此：

SELECT u.first_name, 
    u.last_name, 
    count(case when leadtype_c = 'Referral' then 1 end), 
    count(case when leadtype_c = 'VM' then 1 end), 
    count(case when leadtype_c = 'Email' then 1 end) 
FROM users u 
    JOIN leads l ON u.id = l.assigned_user_id 
    JOIN leads_cstm lc ON l.id = lc.id_c 
GROUP BY u.id 

，以符合您確切的結果，你應該使用一個OUTER JOIN代替，但是這給你的想法。

• A Visual Explanation of SQL Joins