TextJoin like function based on a condition in on SQL

问题

Trying to figure out if it is possible to do a textjoin like function in SQL based on a condition. Right now the only way I can think of doing it is by running a pivot to make the rows of the column and aggregating them that way. I think this is the only way to transpose the data in SQL?

Input This would be a aql table (tbl_fruit) that exists as the image depicts

SELECT * FROM tbl_fruit

Output

回答1:

Below is for BigQuery Standard SQL (without specifically listing each column, thus in a way that it scales ...)

#standardSQL
select `Group`, string_agg(split(kv, ':')[offset(0)], ', ') output
from `project.dataset.table` t,
unnest(split(translate(to_json_string((select as struct t.* except(`Group`))), '{}"', ''))) kv
where split(kv, ':')[offset(1)] != '0'
group by `Group`    

If to apply to sample data from your question - output is

回答2:

In Big Query, you could do this with arrays:

select grp,
    array_to_string(
        [
            case when apples  = 1 then 'apples' end,
            case when oranges = 1 then 'oranges' end,
            case when bananas = 1 then 'bananas' end,
            case when grapes  = 1 then 'grapes' end
        ],
        ','
    ) as output
from mytable

This puts all the columns in an array, transcoding each 1 to the corresponding literal string and 0s to null values. Then array_to_string() builds the output CSV string - this functions ignores null values by default.

来源：https://stackoverflow.com/questions/65345650/textjoin-like-function-based-on-a-condition-in-on-sql