[英]SQL query to search for string in a table?
嗨,我想在存儲在mysql數據庫中的表中搜索特定的字符串。 表格結構如下: -
+--------------------------------------------------------------------------+
| day | 9-10 | 10-11 | 11-12 | 12-1 | 1-2 | 2-3 | 3-4 |
|---------------------------------------------------------------------------
| Monday | DA6210 | DA6220 | DA6010 | | DA6020 | | |
| Tuesday | DA6210 | DA6010 | DA6220 | | DA6020 | | |
| Wednesday | IA6010 | DA6220 | | | DA6020 | | |
| Thursday | IA6010 | | DA6210 | | GC6210 | | |
| Friday | IA6010 | | DA6010 | | GC6210 | | |
| Saturday | DA6210 | | | | | | |
+--------------------------------------------------------------------------+
我想要搜索當天和所有時間的字符串。 對於前者 如果當天是星期四並且代碼是DA6220,它應該返回空集,因為字符串在星期四的所有時間段都不存在。
我已經創建了一個SQL查詢但它沒有按預期工作。 請提供一種方法來做到這一點。
SQl查詢: -
SELECT * from `table` where day='Thursday' AND `9-10`='DA6220' OR `10-11`='DA6220' OR `11-12`='DA6220'
OR `12-1`='DA6220' OR `1-2`='DA6220' OR `2-3`='DA6220' OR `3-4`='DA6220'
SELECT * from `table` where day='Thursday' AND (`9-10`='DA6220' OR `10-11`='DA6220' OR `11-12`='DA6220'
OR `12-1`='DA6220' OR `1-2`='DA6220' OR `2-3`='DA6220' OR `3-4`='DA6220')
看起來你的AND首先被評估。 請嘗試以上方法
已經給出了問題的答案,但是當我查看您的數據時,我會看到一些可以讓您的生活更輕松並增加可能性的東西:您最好創建一個VIEW 。
首先,我稍微修改了你的列名,因為你保留了單詞。
介紹你的新朋友myview
cREATE VIEW myview AS
SELECT wkday, '9-10' AS rng, `9-10` AS cd from `mytable`
UNION
SELECT wkday, '10-11' AS rng, `10-11` AS cd from `mytable`
UNION
SELECT wkday, '11-12' AS rng, `11-12` AS cd from `mytable`
UNION
SELECT wkday, '12-1' AS rng, `12-1` AS cd from `mytable`
UNION
SELECT wkday, '1-2' AS rng, `1-2` AS cd from `mytable`
UNION
SELECT wkday, '2-3' AS rng, `2-3` AS cd from `mytable`
UNION
SELECT wkday, '3-4' AS rng, `3-4` AS cd from `mytable`
;
這是針對您的數據庫的一次性查詢。
您的查看數據是:
SELECT * FROM myview
wkday rng cd
----------------------
Monday 9-10 DA6210
Tuesday 9-10 DA6210
Wednesday 9-10 IA6010
Thursday 9-10 IA6010
Friday 9-10 IA6010
Saturday 9-10 DA6210
Monday 10-11 DA6220
Tuesday 10-11 DA6010
Wednesday 10-11 DA6220
...
創建視圖后,原始查詢編寫起來會更簡單:
它變成了這個:
SELEct rng FROM myview WHERE wkday='Thursday' AND cd='DA6220';
沒有更多的OR,無需無休止地重復您正在尋找的代碼
...如果你想搜索多個代碼,它也是花生:
SELEct rng FROM myview WHERE wkday='Thursday' AND cd IN ('DA6220','IA6010');
但是你的新觀點很酷,你可以簡單地問:
我有代碼'DA6220'的日期或范圍是多少?
天
SELEct wkday FROM myview WHERE cd='DA6220';
結果:
wkday
----------
Tuesday
Wednesday
Monday
范圍
SELEct rng FROM myview WHERE cd='DA6220';
結果:
rng
-----
11-12
10-11
10-11
這是VIEW的典型應用。 它讓您的生活更輕松。
闡述我的評論:
SELECT *
FROM `table`
WHERE 0 < LOCATE("DA6220", CONCAT(
`9-10`, " ", `10-11`, " ", `11-12`, " ",
`12-1`, " ", `1-2`, " ", `2-3`, " ", `3-4`
))
這種方法的好處是你不必重復重復搜索字符串。 它可能比OR
版本略慢。
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