SQL Server's isNumeric() equivalent in amazon redshift

Question

• I\'m using amazon redshift as my data warehouse
• I have a field (field1)of type string. Some of the strings start with four numbers and others with letters:

Answer 1

It looks like the code you are looking for the is the similar to function:

where left(field,4) similar to '[0-9]{4}'

Redshift doc

Answer 2

We have tried the following and worked for most of our scenarios:

columnn ~ '^[-]{0,1}[0-9]{1,}[.]{0,1}[0-9]{0,}$'

This will positive, negative, integer and float numbers.