Implicit Data Type Conversion

Implicit data conversion is not possible in Dialect 3 — the CAST function is almost always required to avoid data type clashes.

In Dialect 1, in many expressions, one type is implicitly cast to another without the need to use the CAST function.For instance, the following statement in Dialect 1 is valid:

The string literal will be cast to the DATE type implicitly.

In Dialect 3, this statement will raise error 35544569, “Dynamic SQL Error: expression evaluation not supported, Strings cannot be added or subtracted in dialect 3” — a cast will be needed:

Or, with a datetime literal:

In Dialect 1, mixing integer data and numeric strings is usually possible because the parser will try to cast the string implicitly.For example,

will be executed correctly.

In Dialect 3, an expression like this will raise an error, so you will need to write it as a CAST expression:

The exception to the rule is during string concatenation.

When multiple data elements are being concatenated, all non-string data will undergo implicit conversion to string, if possible.