Equivalent of string contains in google bigquery

user_10829044 0
Viewed 38246

I have a table like as shown below

enter image description here

I would like to create two new binary columns indicating whether the subject had steroids and aspirin. I am looking to implement this in Postgresql and google bigquery

I tried the below but it doesn't work

select subject_id
case when lower(drug) like ('%cortisol%','%cortisone%','%dexamethasone%') 
then 1 else 0 end as steroids,
case when lower(drug) like ('%peptide%','%paracetamol%') 
then 1 else 0 end as aspirin,
from db.Team01.Table_1


SELECT 
db.Team01.Table_1.drug
FROM `table_1`,
UNNEST(table_1.drug) drug
WHERE REGEXP_CONTAINS( db.Team01.Table_1.drug,r'%cortisol%','%cortisone%','%dexamethasone%')

I expect my output to be like as shown below

enter image description here

google-bigquery postgresql sql
5 Answers

Below is for BigQuery Standard SQL 

#standardSQL
SELECT 
  subject_id,
  SUM(CASE WHEN REGEXP_CONTAINS(LOWER(drug), r'cortisol|cortisone|dexamethasone') THEN 1 ELSE 0 END) AS steroids,
  SUM(CASE WHEN REGEXP_CONTAINS(LOWER(drug), r'peptide|paracetamol') THEN 1 ELSE 0 END) AS aspirin
FROM `db.Team01.Table_1`
GROUP BY subject_id

if to apply to sample data from your question - result is 

Row subject_id  steroids    aspirin  
1   1           3           1    
2   2           1           1

Note: instead of simple LIKE ending with lengthy and redundant text - I am using LIKE on steroids - which is REGEXP_CONTAINS

user_52219440

In Postgres, I would recommend using the filter clause:

select subject_id,
       count(*) filter (where lower(drug) ~ 'cortisol|cortisone|dexamethasone') as steroids,
       count(*) filter (where lower(drug) ~ 'peptide|paracetamol') as aspirin,
from db.Team01.Table_1
group by subject_id;

In BigQuery, I would recommend countif():

select subject_id,
       countif(regexp_contains(drug, 'cortisol|cortisone|dexamethasone') as steroids,
       countif(drug ~ ' 'peptide|paracetamol') as aspirin,
from db.Team01.Table_1
group by subject_id;

You can use sum(case when . . . end) as a more general approach. However, each database has a more "local" way of expressing this logic. By the way, the FILTER clause is standard SQL, just not widely adopted.

user_11440350

Use conditional aggregation. This is a solution that works across most (if not all) RDBMS:

SELECT
    subject_id,
    MAX(CASE WHEN drug IN ('cortisol', 'cortisone', 'dexamethasone') THEN 1 END) steroids,
    MAX(CASE WHEN drug IN ('peptide', 'paracetamol') THEN 1 END) aspirin
FROM db.Team01.Table_1.drug
GROUP BY subject_id

NB: it is unclear why you are using LIKE, since it seems like you are having exact matches; I turned the LIKE condition to equalities.

user_106767160

you have missing group-by

select subject_id,
    sum(case when lower(drug) in ('cortisol','cortisone','dexamethasone')
       then 1 else 0 end) as steroids,
    sum(case when lower(drug) in ('peptide','paracetamol') 
       then 1 else 0 end) as aspirin
from db.Team01.Table_1
group by subject_id

using like keyword

select subject_id,
 sum(case when lower(drug) like '%cortisol%'
        or lower(drug) like '%cortisone%'
        or lower(drug) like '%dexamethasone%'   
    then 1 else 0 end) as steroids,
    sum(case when lower(drug) like '%peptide%'
        or lower(drug) like '%paracetamol%'
    then 1 else 0 end) as aspirin
from db.Team01.Table_1
group by subject_id
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