RapidMiner

Write Database for large dataset

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Contributor II robin
Contributor II

Write Database for large dataset

I am attempting to limit the number of queires supplied back from the Read Database operator. When I write the code in SQL the LIMIT operator does not seem to be valid. What should I be using? 

SELECT `id_unique`
FROM `retrieved_id`
WHERE `id_count` IS NOT NULL
LIMIT 1000

Rapid Miner is giving me the full database back instead of the first 1k rows. 

2 REPLIES
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RM Certified Expert
RM Certified Expert
Solution

Re: Write Database for large dataset

Hi,

 

which database system are you using? 

 

For me it works with PostgreSQL and MySQL, just tested with different limits (1000, 1300, 1500 etc.)

 

The query is interpreted by your database server. RapidMiner just sends it to the database. (If "prepare statement" is checked, a bit differently, you could play with that.)

 

Could you test the same query in some other tool (SQL client like SQuirrel SQL) with the same database?

 

Regards,

Balázs

 

--
Balázs Bárány
Data Scientist, Vienna
https://datascientist.at
Contributor II robin
Contributor II

Re: Write Database for large dataset

For some reason it now likes me and is working as designed.