A standard SATA cable will have an identical connector on either end. Whether or not the cable orientation to the connector is molded at a 90° angle or not is irrelevant. If both ends of the cable are not identical, you either don't have a standard SATA cable, or you're trying to install the wrong cable.
SATA connections on your SSD or spinning platter hard disk will have both a data and power connector. The cable coming from your motherboard is DATA only, therefore you will need to attach a SATA power connection from your power supply to fulfill the larger connector portion of the SATA drive you are attaching to the system.
SATA Power looks like this:
SATA DATA looks like this (notice how the electrical connector is the same on either end, regardless of the 90° molded connector):