SQL_VSIZE1
ORACLE

SELECT ENAME, length(ename) "length",VSIZE(ENAME)"vsize" FROM emp where rownum < 7

POSTGRESQL

SELECT ENAME, length(ename),char_length(ENAME) FROM emp limit 6

MySQL

SELECT ENAME, length(ename)"lname",char_length(ENAME)"c-length" FROM emp limit 6

 
oracle

PostgreSQL

MySQL