Get month name from a valid date. Invalid dates will return blanks.
monthname DATE
monthname 20210601
June
monthname 3214132
''
Input Result
.→-----------------------.
| .→-------. .→--------. |
| ↓20210601| ↓June | |
| |20210701| |July | |
| |20210801| |August | |
| |20210901| |September| |
| |20211006| |October | |
| |20211121| |November | |
| |20211201| |December | |
| |20220105| |January | |
| | 234| | | |
| |20220314| |March | |
| |20220405| |April | |
| |20220505| |May | |
| '--------' '---------' |
'∊-----------------------'