sql_CONCAT拼接SUBSTR截取

CONCAT和SUBSTR不一樣的數據庫有不一樣的語法。

（1）CONCAT

MySQL: CONCAT( )

Oracle: CONCAT( ), ||

SQL Server: +

（2）SUBSTR

MySQL: SUBSTR( ), SUBSTRING( )

Oracle: SUBSTR( )

SQL Server: SUBSTRING( )

（3）具體用法如例：

SELECT CONCAT (Region_Name, Store_Name) FROM Geography  WHERE Store_Name = 'Boston';

查詢結果：EastBoston

SELECT Region_Name || ' ' || Store_Name FROM Geography  WHERE Store_Name = 'Boston';

查詢結果：East Boston

SELECT Region_Name + ' ' + Store_Name FROM Geography WHERE Store_Name = 'Boston';

查詢結果：East Boston

SELECT SUBSTR (Store_Name, 3) FROM Geography WHERE Store_Name = 'Los Angeles';

查詢結果：s Angeles

SELECT SUBSTR (Store_Name, 2, 4) FROM Geography WHERE Store_Name = 'San Diego';

查詢結果：an D