Mysql 的trim() 函式

Mysql 的trim() 函式

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mysql中的去除左空格函式：
LTRIM(str)
Returns the string str with leading space characters removed.
以下是程式碼片段：
mysql> SELECT LTRIM(' barbar');
-> 'barbar'



This function is multi-byte safe.
mysql中的去除右空格函式：
RTRIM(str)
Returns the string str with trailing space characters removed.
以下是程式碼片段：
mysql> SELECT RTRIM('barbar ');
-> 'barbar'



This function is multi-byte safe.
trim函式可以過濾指定的字串：
完整格式：TRIM([{BOTH | LEADING | TRAILING} [remstr] FROM] str)
簡化格式：TRIM([remstr FROM] str)

Returns the string str with all remstr prefixes or suffixes removed. If none of the specifiers BOTH, LEADING,
or TRAILING is given, BOTH is assumed. remstr is optional and, if not specified, spaces are removed.



以下是程式碼片段：
mysql> SELECT TRIM(' bar '); //預設刪除前後空格
-> 'bar'
mysql> SELECT TRIM(LEADING '，' FROM '，，barxxx'); //刪除指定首字元 如'，‘
-> 'barxxx'
mysql> SELECT TRIM(BOTH '，' FROM '，，bar，，，'); //刪除指定首尾字元
-> 'bar'
mysql> SELECT TRIM(TRAILING '，' FROM 'barxxyz，，');
-> 'barxxyz'

mysql> UPDATE table SET `field`=TRIM(TRAILING ',' FROM `FIELD`) WHERE WHERE `FIELD` LIKE '%,';



This function is multi-byte safe.
替換資料庫中欄位的最後一個分頁符
程式碼如下:
UPDATE [!db.pre!]ecms_news_data_1 SET `newstext`=TRIM(TRAILING '[!--empirenews.page--]' FROM `newstext`) WHERE id=585;

SELECT TRIM(TRAILING '[!--empirenews.page--]' FROM `newstext`) AS newstex FROM [!db.pre!]ecms_news_data_1 WHERE id=585;