MySQL查看邏輯與案例

Question

我的任務是編輯我們的MySQL視圖之一，以包含缺失的行。問題是之前的視圖查詢使用的是if（）語句，因爲某些原因我們沒有捕獲所有錶行。我絕不是一個SQL主並不能算出這個...

原始代碼示例：

CREATE VIEW `b2b_data` AS SELECT 
`asteriskcdrdb`.`cdr`.`uniqueid` AS `callid`, 
`asteriskcdrdb`.`cdr`.`calldate` AS `ENTER`, 
if((`asteriskcdrdb`.`cdr`.`dcontext` = 'from-internal'),`asteriskcdrdb`.`cdr`.`did`,`asteriskcdrdb`.`cdr`.`src`) AS `caller_id`, 
if((`asteriskcdrdb`.`cdr`.`dcontext` = 'from-internal'),'outbound','inbound') AS `direction`, 
if((`asteriskcdrdb`.`cdr`.`dcontext` = 'from-internal'),`asteriskcdrdb`.`cdr`.`src`,substr(`asteriskcdrdb`.`cdr`.`dstchannel`,5,3)) AS `AGENT`, 
sec_to_time(`asteriskcdrdb`.`cdr`.`duration`) AS `AGENT_TIME`, 
`asteriskcdrdb`.`cdr`.`disposition` AS `DISPOSITION`, 
if((`asteriskcdrdb`.`cdr`.`dcontext` = 'from-internal'),`asteriskcdrdb`.`cdr`.`dstchannel`,`asteriskcdrdb`.`cdr`.`did`) AS `ROUTE`, 
`asteriskcdrdb`.`cdr`.`recordingfile` AS `RECORDING` FROM `asteriskcdrdb`.`cdr` WHERE (((`asteriskcdrdb`.`cdr`.`dst` = '601') AND (`asteriskcdrdb`.`cdr`.`dcontext` = 'ext-group')) OR ((`asteriskcdrdb`.`cdr`.`dst` = '601') AND (`asteriskcdrdb`.`cdr`.`dcontext` = 'from-internal-xfer')) OR ((`asteriskcdrdb`.`cdr`.`dcontext` = 'from-internal') AND (`asteriskcdrdb`.`cdr`.`src` in ('143','146','317','318','320','225','214')))) 

我看網上說IF ... ELSEIF只適用於存儲過程和函數。所以我放棄了這個想法。然後我想也許我可以使用CASE使查詢返回我需要的。毋庸置疑，這不起作用，顯然是錯誤的......但它確實顯示了我正在嘗試使用的邏輯。

改裝成代碼示例：

CREATE VIEW `b2b_data` AS SELECT 
`asteriskcdrdb`.`cdr`.`uniqueid` AS `callid`, 
`asteriskcdrdb`.`cdr`.`calldate` AS `ENTER`, 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN `asteriskcdrdb`.`cdr`.`did` AS `caller_id`; 
    WHEN 'from-internal-xfer' THEN `asteriskcdrdb`.`cdr`.`src` AS `caller_id`; 
    WHEN 'ext-local' THEN `asteriskcdrdb`.`cdr`.`src` AS `caller_id`; 
    WHEN 'ext-group' THEN `asteriskcdrdb`.`cdr`.`src` AS `caller_id`; 
    WHEN 'from-did-direct' THEN `asteriskcdrdb`.`cdr`.`src` AS `caller_id`; 
END CASE; 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN 'outbound' AS `direction`; 
    WHEN 'from-internal-xfer' THEN 'inbound' AS `direction`; 
    WHEN 'ext-local' THEN 'inbound' AS `direction`; 
    WHEN 'ext-group' THEN 'inbound' AS `direction`; 
    WHEN 'from-did-direct' THEN 'inbound' AS `direction`; 
END CASE; 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN `asteriskcdrdb`.`cdr`.`src` AS `AGENT`; 
    WHEN 'from-internal-xfer' THEN `asteriskcdrdb`.`cdr`.`dst` AS `AGENT`; 
    WHEN 'ext-local' THEN `asteriskcdrdb`.`cdr`.`dst` AS `AGENT`; 
    WHEN 'ext-group' THEN substr(`asteriskcdrdb`.`cdr`.`dstchannel`;5;3)) AS `AGENT`; 
    WHEN 'from-did-direct' THEN `asteriskcdrdb`.`cdr`.`dst` AS `AGENT`; 
END CASE; 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN sec_to_time(`asteriskcdrdb`.`cdr`.`duration`) AS `AGENT_TIME`; 
    WHEN 'from-internal-xfer' THEN sec_to_time(`asteriskcdrdb`.`cdr`.`duration`) AS `AGENT_TIME`; 
    WHEN 'ext-local' THEN sec_to_time(`asteriskcdrdb`.`cdr`.`duration`) AS `AGENT_TIME`; 
    WHEN 'ext-group' THEN sec_to_time(`asteriskcdrdb`.`cdr`.`duration`) AS `AGENT_TIME`; 
    WHEN 'from-did-direct' THEN sec_to_time(`asteriskcdrdb`.`cdr`.`duration`) AS `AGENT_TIME`; 
END CASE; 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN `asteriskcdrdb`.`cdr`.`disposition` AS `DISPOSITION`; 
    WHEN 'from-internal-xfer' THEN `asteriskcdrdb`.`cdr`.`disposition` AS `DISPOSITION`; 
    WHEN 'ext-local' THEN `asteriskcdrdb`.`cdr`.`disposition` AS `DISPOSITION`; 
    WHEN 'ext-group' THEN `asteriskcdrdb`.`cdr`.`disposition` AS `DISPOSITION`; 
    WHEN 'from-did-direct' THEN `asteriskcdrdb`.`cdr`.`disposition` AS `DISPOSITION`; 
END CASE; 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN `asteriskcdrdb`.`cdr`.`dstchannel` AS `ROUTE`; 
    WHEN 'from-internal-xfer' THEN `asteriskcdrdb`.`cdr`.`dstchannel` AS `ROUTE`; 
    WHEN 'ext-local' THEN `asteriskcdrdb`.`cdr`.`did` AS `ROUTE`; 
    WHEN 'ext-group' THEN `asteriskcdrdb`.`cdr`.`did` AS `ROUTE`; 
    WHEN 'from-did-direct' THEN `asteriskcdrdb`.`cdr`.`did` AS `ROUTE`; 
END CASE; 

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN `asteriskcdrdb`.`cdr`.`recordingfile` AS `RECORDING` FROM `asteriskcdrdb`.`cdr` WHERE `asteriskcdrdb`.`cdr`.`src` IN ('143';'146';'317';'318';'320';'225';'214'); 
    WHEN 'from-internal-xfer' THEN `asteriskcdrdb`.`cdr`.`recordingfile` AS `RECORDING` FROM `asteriskcdrdb`.`cdr` WHERE `asteriskcdrdb`.`cdr`.`dst` IN ('143';'146';'317';'318';'320';'225';'214'); 
    WHEN 'ext-local' THEN `asteriskcdrdb`.`cdr`.`recordingfile` AS `RECORDING` FROM `asteriskcdrdb`.`cdr` WHERE `asteriskcdrdb`.`cdr`.`dst` IN ('143';'146';'317';'318';'320';'225';'214'); 
    WHEN 'ext-group' THEN `asteriskcdrdb`.`cdr`.`recordingfile` AS `RECORDING` FROM `asteriskcdrdb`.`cdr` WHERE `asteriskcdrdb`.`cdr`.`dst` = '601'; 
    WHEN 'from-did-direct' THEN `asteriskcdrdb`.`cdr`.`recordingfile` AS `RECORDING` FROM `asteriskcdrdb`.`cdr` WHERE `asteriskcdrdb`.`cdr`.`dst` IN ('143';'146';'317';'318';'320';'225';'214'); 
END CASE; 

Answer 1

你把AS條款在錯誤的地方。整個CASE表達式會生成一個值，您可以將該別名分配給該值。而且，在WHEN子句之間或大小寫之後，您不使用;，因爲這會結束整個查詢。 WHEN條款之間沒有分隔符，整個表達式與其他SELECT列分開，其中,。

CASE `asteriskcdrdb`.`cdr`.`dcontext` 
    WHEN 'from-internal' THEN `asteriskcdrdb`.`cdr`.`did` 
    WHEN 'from-internal-xfer' THEN `asteriskcdrdb`.`cdr`.`src 
    WHEN 'ext-local' THEN `asteriskcdrdb`.`cdr`.`src` 
    WHEN 'ext-group' THEN `asteriskcdrdb`.`cdr`.`src` 
    WHEN 'from-did-direct' THEN `asteriskcdrdb`.`cdr`.`src` 
END CASE AS `caller_id`, 

與其他CASE表達式類似。