I rarely touch SQL, so I don't really have much of an opinion on these matters. However, the last time I did have to touch it, the senior developer on the proj

I rarely touch SQL, so I don't really have much of an opinion on these matters. However, the last time I did have to touch it, the senior developer on the project used this as his personal shibboleth for differentiating junior and senior developers. By his reckoning, junior developers put SQL statements in caps because they were used to seeing that in textbooks. Senior developers would realise the importance of maintainability and use lower case out of respect for the next person to read the code.