如何使用帶CASE語句的CONCAT刪除查詢中的空值

我用case語句試圖內CONCAT但它給我空值表結構

CREATE TABLE `UserInfo` (
    `id` int(11) NOT NULL AUTO_INCREMENT, 
    `user_id` int(11) NOT NULL, 
    `key` varchar(200) NOT NULL, 
    `value` longtext NOT NULL, 
    `created_on` varchar(200) NOT NULL, 
    `updated_on` varchar(200) NOT NULL, 
    `status` int(11) NOT NULL, 
    PRIMARY KEY (`id`) 
) ENGINE=MyISAM AUTO_INCREMENT=111 DEFAULT CHARSET=latin1; 

insert into `UserInfo`(`id`,`user_id`,`key`,`value`,`created_on`,`updated_on`,`status`) 
values (69,11132,'country','India','','',1),(67,11132,'city','Gurgaon','','',1),(68,11132,'state','Haryana','','',1),(66,11132,'address','CyberHub','','',1),(64,11131,'state','Delhi','','',1),(65,11131,'country','India','','',1),(63,11131,'city','','','',1),(62,11131,'address','Lajpat Nagar','','',1),(60,11130,'state','Haryana','','',1),(61,11130,'country','India','','',1),(58,11130,'address','','','',1),(59,11130,'city','Gurgaon','','',1),(787,11130,'password','0192023a7bbd73250516f069df18b500','30-03-2016 06:58:18','30-03-2016 06:58:18',1),(788,11131,'password','04d237e63ebc1acbb3fcacf3e1a846cb','30-03-2016 06:58:18','26-04-2016 07:46:33',1),(789,11132,'password','0192023a7bbd73250516f069df18b500','30-03-2016 06:58:18','24-05-2016 11:47:35',1),(1123,11130,'parent','0','','',1),(1124,11131,'parent','0','','',1),(1125,11132,'parent','0','','',1),(2036,11136,'gcm_id','fLJ8vwS5yWc','04-05-2016 06:01:07','04-05-2016 06:01:07',1),(2035,11136,'push_id','fLJ8vwS5yWc:APA91bFO-hLW5uQqDQTABkilyOd9MzuMRhQMI8uNLRGh4fjaq3Bk1OvFmb7QFVKYpqqJZFPQ78Y1h0349IZuxq0EcxZ8VCHJOTOhhsqi1VxQ2A7TVLY-phDcN6sj80x8R7KoOocQKPLl','04-05-2016 06:01:07','04-05-2016 06:01:07',1),(2993,11570,'transaction_limit','100','16-09-2016 10:34:13','16-09-2016 10:34:13',1),(2992,11570,'otp','461178','16-09-2016 10:32:48','16-09-2016 10:32:48',1),(2991,11570,'password','1e28284f59e926547bb6793ad8723722','16-09-2016 10:32:48','16-09-2016 10:32:48',1),(2990,11570,'imei','353918057482479','16-09-2016 10:32:48','16-09-2016 10:32:48',1),(2989,11570,'push_id','dGxCE33MJgg:APA91bFCzSkvIDEcZcgmmSxVocFNZfLI8owLsdElmF-Et0wUH0mxUbQ9mIZDMjlhqClTOYiSxhSaVBdESwJW6J58hsyEF0LUMgXRTGdnEwWdbHJmm3EZuHDHzniMaJGcCKvALrcxtQt8','16-09-2016 10:32:48','16-09-2016 10:32:48',1),(2987,11570,'gender','Male','16-09-2016 10:32:48','16-09-2016 10:32:48',1),(2026,11136,'gcm_id','fLJ8vwS5yWc','03-05-2016 06:28:52','03-05-2016 06:28:52',1),(2025,11136,'push_id','fLJ8vwS5yWc:APA91bFO-hLW5uQqDQTABkilyOd9MzuMRhQMI8uNLRGh4fjaq3Bk1OvFmb7QFVKYpqqJZFPQ78Y1h0349IZuxq0EcxZ8VCHJOTOhhsqi1VxQ2A7TVLY-phDcN6sj80x8R7KoOocQKPLl','03-05-2016 06:28:52','03-05-2016 06:28:52',1),(2024,11136,'gcm_id','cU6PMImJ9Ms','02-05-2016 17:02:39','02-05-2016 17:02:39',1),(2023,11136,'push_id','cU6PMImJ9Ms:APA91bHA-a_joHtzEBgoAPRxRCXObeJLlCCNSxlCM-jBZKvSUEFvhLZEyqPbbsIDyWc2emZa1yBerOQLGXgzzNKZmcJYCgcF8KBdm9McVBiDKzU_OthjGnROZyTC5EvnI7Z4QivXnokA','02-05-2016 17:02:39','02-05-2016 17:02:39',1),(2022,11136,'gcm_id','cU6PMImJ9Ms','02-05-2016 16:38:55','02-05-2016 16:38:55',1),(2020,11136,'gcm_id','c2sOUeSpIuQ','02-05-2016 16:37:53','02-05-2016 16:37:53',1),(2021,11136,'push_id','cU6PMImJ9Ms:APA91bHA-a_joHtzEBgoAPRxRCXObeJLlCCNSxlCM-jBZKvSUEFvhLZEyqPbbsIDyWc2emZa1yBerOQLGXgzzNKZmcJYCgcF8KBdm9McVBiDKzU_OthjGnROZyTC5EvnI7Z4QivXnokA','02-05-2016 16:38:55','02-05-2016 16:38:55',1),(2019,11136,'push_id','c2sOUeSpIuQ:APA91bGskmvA5VVmxozMHKX3qHc16bdmk9h5gFTEPP8uFUYsO-doGCnkTE-ZtpMGeuuk2YCt3Ja56ey7nIga6aO7wpof2fI5zcgYdFACKvkcddNAlY4UhIO39tfyG3m4DZkmaLqw2Kxu','02-05-2016 16:37:53','02-05-2016 16:37:53',1),(2018,11136,'gcm_id','djRRW-PrS2Q','02-05-2016 16:30:02','02-05-2016 16:30:02',1),(2016,11136,'gcm_id','c2sOUeSpIuQ','02-05-2016 16:25:00','02-05-2016 16:25:00',1),(2017,11136,'push_id','djRRW-PrS2Q:APA91bFbB5SO0wY2TlGCZBmgbZUr0c1FXH5FE22YxOCf4tA7uM1V45T2cTY1aitIQKrf1bjrPB-zZUCDPNdL8-2SYnEawrFTdVjL5w1VuVI2kA89ixlK6jlpmNOoJ7wQnWqQoCFkcd9_','02-05-2016 16:30:02','02-05-2016 16:30:02',1),(2015,11136,'push_id','c2sOUeSpIuQ:APA91bGskmvA5VVmxozMHKX3qHc16bdmk9h5gFTEPP8uFUYsO-doGCnkTE-ZtpMGeuuk2YCt3Ja56ey7nIga6aO7wpof2fI5zcgYdFACKvkcddNAlY4UhIO39tfyG3m4DZkmaLqw2Kxu','02-05-2016 16:25:00','02-05-2016 16:25:00',1),(2014,11136,'gcm_id','djRRW-PrS2Q','01-05-2016 07:38:26','01-05-2016 07:38:26',1),(2013,11136,'push_id','djRRW-PrS2Q:APA91bFbB5SO0wY2TlGCZBmgbZUr0c1FXH5FE22YxOCf4tA7uM1V45T2cTY1aitIQKrf1bjrPB-zZUCDPNdL8-2SYnEawrFTdVjL5w1VuVI2kA89ixlK6jlpmNOoJ7wQnWqQoCFkcd9_','01-05-2016 07:38:26','01-05-2016 07:38:26',1),(2012,11136,'gcm_id','c2sOUeSpIuQ','01-05-2016 07:29:00','01-05-2016 07:29:00',1),(2011,11136,'push_id','c2sOUeSpIuQ:APA91bGskmvA5VVmxozMHKX3qHc16bdmk9h5gFTEPP8uFUYsO-doGCnkTE-ZtpMGeuuk2YCt3Ja56ey7nIga6aO7wpof2fI5zcgYdFACKvkcddNAlY4UhIO39tfyG3m4DZkmaLqw2Kxu','01-05-2016 07:29:00','01-05-2016 07:29:00',1),(2010,11439,'otp','467957','01-05-2016 07:04:42','16-08-2016 10:48:09',0),(2009,11438,'otp','631866','30-04-2016 09:36:54','06-05-2016 13:32:15',0),(2008,11438,'otp','586481','30-04-2016 09:22:55','06-05-2016 13:32:15',0),(2007,11438,'otp','971411','30-04-2016 09:19:52','06-05-2016 13:32:15',0),(2006,11136,'gcm_id','eNJISa-1OGA','30-04-2016 09:05:22','30-04-2016 09:05:22',1),(2005,11136,'push_id','eNJISa-1OGA:APA91bGB6m0d-RzoFUvw1SRsCIOEvfO3BjLUiMsZRdHnHlEGq6QKV9sVqCdLai25_dxTvUeuQVzFU5scKCaPvlDaG_VZ-V51t1AG4EEAtJdjGNQwhITF2eh0E24D_J9vPCQ3nIzanq8f','30-04-2016 09:05:22','30-04-2016 09:05:22',1),(2004,11445,'transaction_limit','2000','30-04-2016 09:03:41','30-04-2016 09:03:41',1),(2003,11445,'otp','230253','30-04-2016 09:02:35','30-04-2016 09:02:35',1),(2002,11445,'password','25d55ad283aa400af464c76d713c07ad','30-04-2016 09:02:35','30-04-2016 09:02:35',1),(2001,11445,'push_id','ccPZg_PD7bo:APA91bFrUK8JPZfI6tSBKDgETeeI_aE6RA-FTFh6pS4fluVv6jHIVKUyDAEurIJWo49nWa52q6Zas7F2DI_KNkDX-HVq_TXuO36dRN9JditQVGR9HUq8avS5QEzYA2gwYjyo7Bosrsyz','30-04-2016 09:02:35','30-04-2016 09:02:35',1),(2000,11445,'gcm_id','ccPZg_PD7bo','30-04-2016 09:02:35','30-04-2016 09:02:35',1),(1999,11445,'gender','Male','30-04-2016 09:02:35','30-04-2016 09:02:35',1),(1998,11445,'bank_name','DCB Bank','30-04-2016 09:02:35','30-04-2016 09:02:35',1),(1997,11136,'gcm_id','cXK3F2L7Fcw','30-04-2016 08:37:01','30-04-2016 08:37:01',1)

我試圖與查詢，但其產生空列值以及我想忽略空值

SELECT 
    CONCAT(
    CASE WHEN ui.key='gender' THEN ui.value ELSE '' END, 
    CASE WHEN ui.key='password' THEN ui.value ELSE '' END, 
    CASE WHEN ui.key='transaction_limit' THEN ui.value ELSE '' END 
) AS test, 
    ui.id,ui.user_id,ui.key,ui.value 
FROM UserInfo ui 
WHERE ui.user_id=11445 

Result : 
------------------------------------------------------------------------------------------------------------------ 
test id user_id key     value 
2000 2004 11445 transaction_limit 2000 
     2003 11445 otp     230253 
25d55ad 2002 11445 password    25d55ad.. 
     2001 11445 push_id    ccPZg_P.. 
     2000 11445 gcm_id    ccPZg_PD7bo 
Male 1999 11445 gender    Male 
     1998 11445 bank_name    DCB Bank 

------------------------------------------------------------------------------------------------------------------ 

Desire Result : 
------------------------------------------------------------------------------------------------------------------ 
test id user_id key     value 
2000 2004 11445 transaction_limit 2000 
25d55ad 2002 11445 password    25d55ad.. 
Male 1999 11445 gender    Male 

------------------------------------------------------------------------------------------------------------------

來源

2016-09-23 oxygen

可以使用COALESCE函數定義的任何用戶更換空值值。 –

我嘗試與coalesce結合，但它搞砸了結果 – oxygen

測試列有值與匹配字段和無與倫比的字段以及 – oxygen

對不起，wron答案：

您可以添加有：

SELECT 
    CONCAT(
    CASE WHEN ui.key='gender' THEN ui.value ELSE '' END, 
    CASE WHEN ui.key='password' THEN ui.value ELSE '' END, 
    CASE WHEN ui.key='transaction_limit' THEN ui.value ELSE '' END 
) AS test, 
    ui.id,ui.user_id,ui.key,ui.value 
FROM UserInfo ui 
WHERE ui.user_id=11445 
HAVING test <> '';

樣品

mysql> SELECT 
    -> CONCAT(
    ->  CASE WHEN ui.key='gender' THEN ui.value ELSE '' END, 
    ->  CASE WHEN ui.key='password' THEN ui.value ELSE '' END, 
    ->  CASE WHEN ui.key='transaction_limit' THEN ui.value ELSE '' END 
    -> ) AS test, 
    -> ui.id,ui.user_id,ui.key,ui.value 
    -> FROM UserInfo ui 
    -> WHERE ui.user_id=11445 
    -> HAVING test <> ''; 
+----------------------------------+------+---------+-------------------+----------------------------------+ 
| test        | id | user_id | key    | value       | 
+----------------------------------+------+---------+-------------------+----------------------------------+ 
| 2000        | 2004 | 11445 | transaction_limit | 2000        | 
| 25d55ad283aa400af464c76d713c07ad | 2002 | 11445 | password   | 25d55ad283aa400af464c76d713c07ad | 
| Male        | 1999 | 11445 | gender   | Male        | 
+----------------------------------+------+---------+-------------------+----------------------------------+ 
3 rows in set (0,00 sec) 

mysql>

來源

2016-09-23 10:54:50

謝謝親愛的。這是工作。你節省了我的時間。你能不能讓我知道爲什麼「測試」欄不能在where子句中工作而不是在？ – oxygen

@oxygen - 與WHERE你只減少你在你的查詢中使用的行，並讓你在查詢後減少reseltset。所以隨着havig你可以計數或concat所有行，然後你可以recude這個reseltset像HAVING count> 5或其他 –

您可以使用CONCAT_WS而不是CONCAT。第一ARG通過CONCAT_WS IST的separetor

樣品

mysql> select CONCAT('a','b',NULL,'d','e'); 
+------------------------------+ 
| CONCAT('a','b',NULL,'d','e') | 
+------------------------------+ 
| NULL       | 
+------------------------------+ 
1 row in set (0,01 sec) 

mysql> select CONCAT_WS(',','a','b',NULL,'d','e'); 
+-------------------------------------+ 
| CONCAT_WS(',','a','b',NULL,'d','e') | 
+-------------------------------------+ 
| a,b,d,e        | 
+-------------------------------------+ 
1 row in set (0,00 sec) 

mysql>

手冊：

CONCAT_WS（）代表連接具有分離器和一個特殊的形式CONCAT的（）。第一個參數是其餘參數的分隔符。在字符串之間添加分隔符以連接。分隔符可以是一個字符串，其餘的參數也可以如此。

如果分隔符爲NULL，則結果爲NULL;所有其他NULL值都被跳過。這使得CONCAT_WS（）適合於當你想要連接某些值並且避免在之一爲NULL時丟失所有信息。

來源

2016-09-23 08:24:21

這不是按我的願望解決方案，而我去與GROUP_CONCAT它考慮空值 – oxygen

@oxygen - 我有添加一個新的答案給你 - 對不起，第一個 –

如何使用帶CASE語句的CONCAT刪除查詢中的空值

回答

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