SQL REVERSE function is used to return reverse of a string. It’s supported by MS SQL Server, MySQL. Oracle supports it too, but maybe not in the documents.
SQL LEFT() function is used to get left part of a string with the length of specified number. It is supported by MySQL, MS SQL Server, Access, but not by Oracle.
SQL SPACE() function is used to return space characters, the number of the characters is indicated by the interger parameter. It is supported by MySQL and MS SQL Server, but not Oracle.
SQL ASCII function is used to return ASCII code of a character, if the parameter is a string, it will return the ASCII code of the most left character.
The SQL TRIM() function is used to remove the leading or trailing spaces of a string. Different databases have different writtings: SQL Server LTRIM(), RTRIM() Oracle LTRIM(), RTRIM() MySQL TRIM(), LTRIM(), RTRIM() In SQL Server or Oracle it doesn’t have Trim() function, we can combine LTrim() and RTrim(): RTRIM(LTRIM(str))
The SQL MID() function is used to get part of a string. It’s supported by MySQL, but not by MS SQL Server or Oracle. In SQL Server, Oracle databse, we can use SQL SUBSTRING or SQL SUBSTR instead.
SQL LENGTH or SQL LEN Function is used to get the length of a string. Different databases have different writtings: SQL Server LEN Oracle LENGTH MySQL LENGTH
The SQL Replace function is used to replace every occurrences of a specified string with a replacement string.
SQL CONCAT Function is used to Concatenate (combine) 2 or more strings. Different databases have different writtings: SQL Server + Oracle CONCAT(), || MySQL CONCAT()
SQL SUBSTRING function is used to get part of a string. Different databases have different writtings: SQL Server SUBSTRING() Oracle SUBSTR() MySQL SUBSTR(), SUBSTRING()
