Substring function

The capital of Sweden is Stockholm. Both words start with the letter 'S'. The SQLite substr function returns a substring from a string starting at a specified position with a predefined length. The syntax is substr( string, start, length ) If the start is a positive integer, the substr() function returns a substring starting from the beginning of the string. The first character has an index of 1. If the start is a negative integer, the returned substring consists of the length number of character starting from the end of the string. The last character has an index of -1.

Show the name and the capital where the first letters of each match. Don't include countries where the name and the capital are the same word.