> Given a Python program, you cannot know whether or not it will produce type errors at run-time without executing the program.
Like you mentioned earlier, if you refrain from changing types, a compiler can theoretically determine Python types as well. The Typescript type checker when run on Javascript code is able to do this. But that puts all the onus on you to be super careful instead of letting the language hold your hand.
> SQL can provide the same guarantees as Typescript.
1. It cannot as it does not provide guarantees about its memory model. Declaring a variable as a given type does not guarantee the variable will be created with that type. Typescript does guarantee that when you declare a type that's what the variable type is going to be.
2. As SQL is dynamically typed, allowing you to change the type of a variable mid-execution, what type a variable is depends on when that statement is up for execution. And as SQL is not processed sequentially, at least not in a meaningful sense, it is impossible for a compiler to determine when in the sequence it will end up being called upon.
Like you mentioned earlier, if you refrain from changing types, a compiler can theoretically determine Python types as well. The Typescript type checker when run on Javascript code is able to do this. But that puts all the onus on you to be super careful instead of letting the language hold your hand.
> SQL can provide the same guarantees as Typescript.
1. It cannot as it does not provide guarantees about its memory model. Declaring a variable as a given type does not guarantee the variable will be created with that type. Typescript does guarantee that when you declare a type that's what the variable type is going to be.
2. As SQL is dynamically typed, allowing you to change the type of a variable mid-execution, what type a variable is depends on when that statement is up for execution. And as SQL is not processed sequentially, at least not in a meaningful sense, it is impossible for a compiler to determine when in the sequence it will end up being called upon.