How do you set a users password to "password" on an platform instance via SQL?

An easy solution is simply to do this:

update sso_password_history set ssoph_user_password = '1000:7d46c3df80356a19603c594d306e546d20056024abb0f780:62d069dab1ce5ef8bd1de3b9eb8fbfcf1178a3f006ca1c8b:1'
where ssoph_ssopr_id = (select ssopr_id from sso_principal where ssopr_user_name = 'theusername')

You lose the history of older passwords, but often for the kind of users you are trying to do this for, that really doesn't matter.

Updated method for 2025.  Set all users password to "password".  Better way which makes them not have to change the password on first login.

insert into plt_sso_replication(ssorp_id, ssorp_user_name, ssorp_source_application, ssorp_active_status_cd, ssorp_action_cd, ssorp_created_date, ssorp_modified_date, ssorp_enterprise_name, ssorp_email_address, ssorp_locale_language, ssorp_locale_country, ssorp_access_mode) (select plt_sso_replication_seq.nextval, ent_name, $YOUR_VCID$, 'Active', 'InsertEnterprise', systimestamp, systimestamp, ent_name, null, null, null, null from enterprise where ent_name ='$YOUR_ENTERPRISE$');

insert into plt_sso_replication(ssorp_id, ssorp_user_name, ssorp_source_application, ssorp_active_status_cd, ssorp_action_cd, ssorp_created_date, ssorp_modified_date, ssorp_enterprise_name, ssorp_email_address, ssorp_locale_language, ssorp_locale_country, ssorp_access_mode) (select plt_sso_replication_seq.nextval, user_name, $YOUR_VCID$, 'Active', 'InsertUser', systimestamp, systimestamp, ent_name, email_address, locale_language, locale_country, access_mode from users where user_name IN (select distinct user_name from usro where is_active =1 ));

insert into plt_sso_replication(ssorp_id, ssorp_user_name, ssorp_source_application, ssorp_active_status_cd, ssorp_action_cd, ssorp_created_date, ssorp_modified_date, ssorp_enterprise_name, ssorp_email_address, ssorp_locale_language, ssorp_locale_country, ssorp_access_mode) (select plt_sso_replication_seq.nextval, user_name, $YOUR_VCID$, 'Active', 'GrantAppAccess', systimestamp, systimestamp, ent_name, email_address, locale_language, locale_country, access_mode from users where user_name IN (select distinct user_name from usro where is_active= 1));

update sso_principal set ssopr_last_login_date = '25-MAR-25', ssopr_active_status_cd = 'Active';

update sso_password_history set ssoph_user_password='1000:7d46c3df80356a19603c594d306e546d20056024abb0f780:62d069dab1ce5ef8bd1de3b9eb8fbfcf1178a3f006ca1c8b:1';