…there was Good Morning, Miss Bliss. It was only one season long (1988-89), and aired on the Disney Channel. It was originally pitched to NBC, but they passed. After the show was cancelled after 13 episodes, NBC reformatted it into Saved by the Bell. The main difference was that Miss Bliss focused on the teacher, where as, SbtB focused on the kids.

Zach, Lisa, and Screech were on ‘Miss Bliss,’ along with Mr. Belding – all played by there later SbtB actor counter-parts. The original pilot for ‘Miss Bliss,’ however, starred Austin Green (90210), Jaleel White (Family Matters), and the late Jonathan Brandis (seaQuest DSV).

The episodes of Good Morning, Miss Bliss were later retconned into the history of ‘Saved.’

According to the Wiki:

The series [Good Morning, Miss Bliss] was integrated into the Saved by the Bell syndicated rerun package; episodes from this series were later introduced with a cold open by Mark-Paul Gosselaar explaining that these were from an earlier time frame than the rest of the series (despite the fact that the previous series was, for all intents and purposes, a different continuity), along with a retrofitted version of the regular Saved by the Bell opening theme.

Source: Dave Ryan Show and then Wiki-wiki.