If condition in SQL file vertica - sql

Question

I need to execute insertions for around 10 tables, before inserting I have to check for a condition, condition remains the same for each of the tables, instead of giving that condition within insert query, I wish I could give in if condition (a select query), if satisfied then execute insert statements, is there a way to give if condition in Vertica SQL file ? If condition is not satisfied I dont want to execute any of the insert queries.

Answer 1

If the condition is, for example, that you only insert the data on a Sunday, try this:
a) a test table:
CREATE LOCAL TEMPORARY TABLE input(id,name)
ON COMMIT PRESERVE ROWS AS
SELECT 42,'Arthur Dent'
UNION ALL SELECT 43,'Ford Prefect'
UNION ALL SELECT 44,'Tricia McMillan'
KSAFE 0;
From this table, select with a WHERE condition that tests whether it's sunday -- that's all, see here:
SELECT
*
FROM input
WHERE TRIM(TO_CHAR(CURRENT_DATE,'Day'))='Sunday'
;
id|name
42|Arthur Dent
43|Ford Prefect
44|Tricia McMillan
With a different value for the week day (I'm writing this on a Sunday...), you get this:
SELECT
*
FROM input
WHERE TRIM(TO_CHAR(CURRENT_DATE,'Day'))='Monday'
;
id|name
select succeeded; 0 rows fetched
I use this technique in SQL generating SQL to create a script or an empty file determining on circumstances, and then to call that script (full or empty), implementing a conditional SQL execution that way....

Answer 2

I know it is an old post, but i want to share what i recently solved my problem.
I need to insert in one table or another based on some condition. You first should have a field or value what will be your search condition.
create table tmp1 (
Col1 int null
,Col2 varchar(100) null
)
--Insert values
insert into tmp (Col1,Col2) Values
(1,'Text1')
,(2,'Text2')
--Insert into table001
insert into table001
select
t.field1
,t.field2
,......
from table1 t
inner join tmp t2
on t2.col1 = t.ColX
where 1 = case when t2.Col2 = 'Text1' then 1 else 0 end --Search condition; if 1<>0 then it doesn't do anything; otherwise insert.
--Insert into table002
insert into table002
select
t.field1
,t.field2
,......
from table2 t
inner join tmp t2
on t2.col1 = t.ColX
where 1 = case when t2.Col2 = 'Text2' then 1 else 0 end --Search condition; if 1<>0 then it doesn't do anything; otherwise insert.
Or you can use an UNION/UNION ALL based on this if it is the same working table.
Regards!