Replace this "switch" statement by "if" statements to increase readability.

[AuroraLiu0823]

Code Path:server/src/main/java/org/apache/iotdb/db/mpp/plan/analyze/ExpressionUtils.java switch statements are useful when there are many different cases depending on the value of the same expression. For just one or two cases however, the code will be more readable with if statements.

[GuanchuShen]

[WeOpen Star]I would like to help

[wjr4hy]

[WeOpen Star]I would like to help

[nikam14]

I would like to help, You can assign it to me