How to run alternative where condition if row is zero - mysql

Question

Suppose i have a table
table
+-------------+
| id | name |
+-------------+
| 1 | xabx |
| 2 | abxd |
| 3 | axcd |
| 4 | azyx |
| 5 | atyl |
| 6 | aksd |
| 7 | baabc|
| 8 | aabcd|
+-------------+
first i have to get data if matches first some char like :
if name = aab
then have to run select * from table where name like 'aab%'
then it returns
+-------------+
| 8 | aabcd |
+-------------+
which execatlly i want
but if i have only abc
then the above query return 0 row
then i have to search from middle like :
select * from table where name like '%abc%'
then it returns which is the alternative
+-------------+
| 7 | baabc|
| 8 | aabcd|
+-------------+
i have no much knowledge about mysql is there any query which can do like if first where condition don't have row then run alternative where condition
i have tried this but didn't work as i want.
select * from table where name like 'abc%' or name like '%abc%'
fiddle
thanks in advance

Answer 1

This is somewhat your desired result:
select *from t
where (case
when name like 'abc' then 1
when name like 'bc%' then 1
when name like '%bc' then 1
when name like '%bc%' then 1
else null
end)
order by name
limit 1;
I just put all the combinations as conditions.
You can interchange their sequence or remove unnecessary condition.
limit 1 makes only 1 row visible for whichever condition satisfies.
Here is the answer from your fiddle. Check it out
Hope it helps!

Answer 2

This is a possible solution:
Left joining the table on itself, where the table is initially filtered by the more inclusive %bx% and then the join is filtered by the more restrictive bx%.
This allows you to use the joined name if it exists, but revert to the original if not:
SELECT t1.id, IF(t2.name IS NULL, t1.name, t2.name) name
FROM test t1
LEFT JOIN test t2 ON t2.id = t1.id AND t1.name like 'bx%'
WHERE t1.name LIKE '%bx%'
This may/may not be ideal depending on the size or your dataset.

Answer 3

COUNT checking may work
select *
from table
where name like 'aab%' or
((select count(*) from table where name like 'aab%') = 0 and name like '%abc%')
I guess that it would be a good idea to compute the count value into a variable first, however, the optimizer may recognize independent subquery anyway and run it once.