spark sql是否區分大小寫？

Question

看起來spark sql對“喜歡”的查詢區分大小寫，對嗎？

spark.sql("select distinct status, length(status)  from table")

返回

Active|6

spark.sql("select distinct status  from table where status like '%active%'")

不返回任何值

spark.sql("select distinct status  from table where status like '%Active%'")

返回

 Active

Answer 1

是的，Spark區分大小寫。 對於字符串比較，大多數RDBMS默認區分大小寫。 如果您想要不區分大小寫，請嘗試rlike或將列轉換為大寫/小寫。

scala> val df = Seq(("Active"),("Stable"),("Inactive")).toDF("status")
df: org.apache.spark.sql.DataFrame = [status: string]

scala> df.createOrReplaceTempView("tbl")

scala> df.show
+--------+
|  status|
+--------+
|  Active|
|  Stable|
|Inactive|
+--------+


scala> spark.sql(""" select status from tbl where status like '%Active%' """).show
+------+
|status|
+------+
|Active|
+------+


scala> spark.sql(""" select status from tbl where lower(status) like '%active%' """).show
+--------+
|  status|
+--------+
|  Active|
|Inactive|
+--------+


scala>