PHP: 5.6.4
Computer: 64 bits
Thread Safety: Enable
SQL Sever 2017


I add 'extension=php_sqlsrv_56_ts.dll', 'extension=php_pdo_sqlsrv_56_ts.dll' in php.ini like
;extension=php_pdo_pgsql.dll
extension=php_pdo_sqlite.dll
**extension=php_sqlsrv_56_ts.dll
extension=php_pdo_sqlsrv_56_ts.dll**
;extension=php_pgsql.dll
Additionally, I checked php version, computer bits, and thread-safety between xampp and ddl.
I also tried adding 'php_sqlsrv_55/52_nts.dll' and php_pdo_sqlsrv_56_ts.dll in 32 bits.
the result is like

For your information, it worked well when I added 'extension=php_pdo_odbc.dll'.
I followed the best answer in
Fatal error: Call to undefined function sqlsrv_connect() in C:\xampp\htdocs