Question

I’m trying to get the MIN value from both tables (one return value).

Following mysql structure + data:

table_master

`ID` (Unique) | `Amount`

1 | 5.8
2 | 22.1
3 | 44.22

---

table_variants

`table_master_ID` | `Amount`

1 | 4.11
1 | 5.12
1 | 
1 |
2 | 9.22
3 | 

---

With this query:

SELECT table_master.Amount, table_variants.Amount 
FROM table_master 
LEFT JOIN table_variants ON table_master.ID = table_variants.table_master_ID 
WHERE table_master.ID = 1

I get something like this:

5.8 | 4.11
5.8 | 
5.8 | 5.12
...

Now I need the MIN Amount value of both tables.
ID of table_master is unique, data in table_variants is optional.

How can I do this? I was trying MIN() with CASE() but without success.

Any hints?

TIA!

Answer 1

SELECT MIN(t.Amount) FROM
(SELECT Amount FROM table_master WHERE ID = 1
 UNION SELECT Amount FROM table_variants WHERE table_master_ID = 1) AS t

MySQL UNION Syntax

SELECT MIN(LEAST(table_master.Amount, table_variants.Amount))
FROM table_master 
LEFT JOIN table_variants ON table_master.ID = table_variants.table_master_ID 
WHERE table_master.ID = 1

MySQL LEAST Function