SQL 通过 dbgetQuery 使用 CASE WHEN 查询不起作用

Question

我有一个问题：我在 R 中测试了 CASE WHEN SQL 查询，但我得到了一个错误。能否请您提出解决方案？

这里是重现的代码：

library(sparklyr)
library(gapminder)
spark_conn <- spark_connect(master = "local")
data("gapminder")
copy_to(spark_conn, gapminder)
src_tbls(spark_conn)

#The query gave an error
DBI::dbGetQuery(spark_conn, "
                SELECT *
                CASE WHEN pop > 100000000 THEN 'Biggy'
                WHEN pop < 10000000 THEN 'Small'
                ELSE 'Medium' END
                AS pop_category
                FROM gapminder 
                WHERE year = 1957
                ")


Error: org.apache.spark.sql.catalyst.parser.ParseException: 
mismatched input 'WHEN' expecting <EOF>(line 3, pos 21)

== SQL ==

                SELECT *
                CASE WHEN pop > 10000000 THEN 'Biggy'
---------------------^^^
                WHEN pop < 10000000 THEN 'Small'
                ELSE 'Medium' END
                AS pop_category
                FROM gapminder

Answer 1

* 后缺少逗号 ,。只需在它后面添加逗号，您的查询就可以正常工作

SELECT *,
    CASE WHEN pop > 100000000 THEN 'Biggy'
    WHEN pop < 10000000 THEN 'Small'
    ELSE 'Medium' END
    AS pop_category
FROM gapminder 
WHERE year = 1957

SQL 通过 dbgetQuery 使用 CASE WHEN 查询不起作用

SQL query with CASE WHEN by dbgetQuery does not work

sql

r

dbi

sparklyr