CCode should be convenient to read, not convenient to write.
There are several things involved here. Choosing good names that are self-explanatory is a good place to start. Strive for simple solutions, even if they are more verbose or inefficient. Whether inefficiency is a problem won’t be known until profiling is done later in the project, in a real production situation.
Choose style and formatting conventions early in the project, and conform to them. Require that everyone conform to them. This will be easier to do if everyone has a hand in deciding on the conventions and buys into them. This will make the code uniform and thus easier to read.
And get rid of any and all duplication.
Do you format your code? Your queries? Using what guidelines?