<s>[INST] I have this SQL error, what's the problem? : AN SQLSTATE OR SQLCODE VARIABLE DECLARATION IS IN A NESTED COMPOUND STATEMENT [/INST] The error message "AN SQLSTATE OR SQLCODE VARIABLE DECLARATION IS IN A NESTED COMPOUND STATEMENT" typically indicates that you have declared an SQLSTATE or SQLCODE variable inside of a nested BEGIN...END compound statement in your SQL code.

In many SQL implementations, including DB2 and PostgreSQL, you are not allowed to declare an SQLSTATE or SQLCODE variable inside of a nested BEGIN...END block. The variable must be declared outside of any nested blocks, at the same level as the main program logic.

To resolve this issue, move the declaration of the SQLSTATE or SQLCODE variable outside of any nested BEGIN...END blocks. If you need to use the variable within a nested block, you can use a global variable or pass the variable as a parameter to the nested block.

Here's an example to demonstrate the correct usage:

```
DECLARE sqlstate CHAR(5);

BEGIN
  ...
  ...
END;
```</s>