SQL
Underscores in Numeric Literals
DuckDB's SQL dialect allows using the underscore character `_` in numeric literals as an optional separator. The rules for using underscores are as follows:  
* Underscores are allowed in integer, decimal, hexadecimal and binary notation.
* Underscores can not be the first or last character in a literal.
* Underscores have to have an integer/numeric part on either side of them, i.e., there can not be multiple underscores in a row and not immediately before/after a decimal or exponent.  
Examples:  
```sql
SELECT 100_000_000;          -- 100000000
SELECT '0xFF_FF'::INTEGER;   -- 65535
SELECT 1_2.1_2E0_1;          -- 121.2
SELECT '0b0_1_0_1'::INTEGER; -- 5
```