Example:
dbadmin=> SELECT left('Vertica is cool!', 7), right('Everybody loves Vertica', 7);
left | right
--------+---------
Vertica | Vertica
(1 row)
Unfortunately, the LEFT and RIGHT SQL functions won’t work on table columns having the LONG VARCHAR data type where the data size can be up to 32000000 octets.
dbadmin=> \d big_stuff;
List of Fields by Tables
Schema | Table | Column | Type | Size | Default | Not Null | Primary Key | Foreign Key
-------+-----------+--------+-----------------------+---------+---------+----------+-------------+-------------
public | big_stuff | c1 | int | 8 | | f | f |
public | big_stuff | json | long varchar(1048576) | 1048576 | | f | f |
(2 rows)
dbadmin=> SELECT LEFT(json, 10) json_left_10_chars,
dbadmin-> RIGHT(json, 10) json_right_10_chars
dbadmin-> FROM big_stuff;
ERROR 3457: Function LEFT(long varchar, int) does not exist, or permission is denied for LEFT(long varchar, int)
HINT: No function matches the given name and argument types. You may need to add explicit type casts
Alternatively, we can use the SBSTR function to find characters from the left and right side of a LONG VARCHAR!
dbadmin=> SELECT SUBSTR(json, 1, 10) json_left_chars,
dbadmin-> SUBSTR(json, LENGTH(json)-9) json_right_10_chars
dbadmin-> FROM big_stuff;
json_left_chars | json_right_10_chars
----------------+---------------------
"c": "6EgQ | zXppo4Yi"}
(1 row)
Helpful Links:https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Functions/String/LEFT.htm
https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Functions/String/RIGHT.htm
https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Functions/String/SUBSTR.htm
https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/DataTypes/LongDataTypes.htm
Have fun!
About the Author
James Knicely
Vertica Field Chief Technologist
I've had the privilege of working with many database technologies in my career. But after being introduced to Vertica in May of 2011 as a client, I was hooked on the new technology after witnessing a query run in milliseconds that had previously ran for hours on the legacy database we had in place. It was then that I knew I wanted to eventually join the Vertica team, and 4 years later I did! I am currently a Vertica evangelist and am ready to help you get on board! Please feel free to reach out to me with any questions you have about Vertica and make sure to follow my Vertica Quick Tips!
