ORACLE Regular Expression solves inconsistent original data formats

Some data formats may be incorrect when basic user data is converted ..

Some data formats may be incorrect when basic user data is converted ..

For example: 2000-1-1 ==> 2000-01-01, 2000-01-1 ==> 2000-01-01, 2000-1-01 ==> 2000-01-01
I used to write a function/procedure script and a large number of IF ELSE scripts...
This time, we accidentally discovered that oracle10g already supports the regular expression function, and the above problem was solved ..
The Code is as follows:
UPDATE lz1_eq_rhgl lzrh set ls1_sp_ghtime = SUBSTR (lz1_sp_ghtime, 1, 5) | '0' | SUBSTR (lz1_sp_ghtime, 6, 2) | '0' | SUBSTR (8, 1) WHERE RETEXT_LINE (lz1_sp_ghtime, '^ \ d {4}-\ d {1}-\ d {1} $ ')