Condition in creating view - liquibase xml - sql

Question

I want to make some view but with condition in my fourth column.
CONDITION:
If epr.j_id is not null then fill lj.id BUT WHEN epr.j_id is null then fill 'NONE'
I've found some condition tag there but I have no idea how I can use it or maybe there is some another way...
<changeSet id="103" author="m">
<createView replaceIfExists="true"
schemaName="public"
viewName="report">
SELECT DISTINCT l.id,
l.name,
l.gis_ext_id AS gis_ext_id_line,
condition (epr.j_id is not null ),

Answer 1

From a previous StackOverflow question: How to add condition to changeSet
If you want to update the columns datatype depending on certain conditions, you can use <preConditions> with <sqlCheck>, and then use <modifyDataType>.
So supposing that there's already a table with name TASK and it contains a column named STATUS, you can modify it's datatype as such:
<changeSet id="1" author="xxx">
<comment>Update Asset table</comment>
<preConditions onFail="MARK_RAN">
<and>
<columnExists tableName="TASK" columnName="STATUS"/>
<sqlCheck expectedResult="0"> SELECT COUNT(*) FROM TASK WHERE STATUS = "pending";</sqlCheck>
</and>
</preConditions>
<modifyDataType tableName="TASK" columnName="STATUS" newDataType="VARCHAR(10)"/>
</changeSet>
Or perhaps you'd like another onFail-behaviour. Check out this link
HALT - Immediately halt execution of entire change log [default]
CONTINUE - Skip over change set. Execution of change set will be attempted again on the next update. Continue with change log.
MARK_RAN - Skip over change set, but mark it as ran. Continue with change log
WARN - Output warning and continue executing change set as normal.
Additional Documentation:
Liquibase: Create View
Mohit Goyal: Check database state and conditionally apply changes in the Liquibase