| Language | const | let | var | let mut |
|---|---|---|---|---|
| C | Immutable variable | Mutable variable | Mutable variable | Not supported |
| Java | Immutable variable | Mutable variable | Mutable variable | Not supported |
| Python | Immutable variable | Mutable variable | Not supported | Not supported |
| JavaScript | Immutable variable | Mutable variable | Mutable variable | Not supported |
| PHP | Immutable variable | Mutable variable | Not supported | Not supported |
| Ruby | Immutable variable | Mutable variable | Not supported | Not supported |
| Swift | Immutable variable | Mutable variable | Not supported | Mutable variable |
| Kotlin | Immutable variable | Mutable variable | Not supported | Not supported |
| TypeScript | Immutable variable | Mutable variable | Mutable variable | Not supported |
| C++ | Immutable variable | Mutable variable | Mutable variable | Mutable variable |
| C# | Immutable variable | Mutable variable | Mutable variable | Not supported |
| Go | Immutable variable | Mutable variable | Not supported | Not supported |
| R | Immutable variable | Mutable variable | Not supported | Not supported |
| MATLAB | Immutable variable | Mutable variable | Not supported | Not supported |
| Objective-C | Immutable variable | Mutable variable | Not supported | Not supported |
| Perl | Immutable variable | Mutable variable | Not supported | Not supported |
| Scala | Immutable variable | Mutable variable | Not supported | Mutable variable |
| Shell | Immutable variable | Mutable variable | Not supported | Not supported |
| SQL | Not supported | Not supported | Not supported | Not supported |
| Lua | Immutable variable | Mutable variable | Not supported | Not supported |
Note that this table is a generalization and that some languages may have slightly different semantics for these keywords. Also, some languages may not support all of these keywords or may use alternative syntax for variable declaration.