COALESCE with Hive SQL

Question

Since there is no IFNULL  ISNULL  or NVL function supported on Hive  I m having trouble converting NULL to 0   I tried COALESCE  column name   0  but received the below error message      Argument type mismatch 0  The expressions after COALESCE should all   have the same type   bigint  is expected but  int  is found   How to resolve this

User · Answer

nvl value defaultvalue  as Columnname   will set the missing values to defaultvalue specified

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If customer primary contact medium is email  if email is null then phonenumber  and if phonenumber is also null then address  It would be written using COALESCE as  coalesce email phonenumber address     while the same in hive can be achieved by chaining together nvl as   nvl email nvl phonenumber nvl address  n a

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As Lamak pointed out in the comment  COALESCE column  CAST 0 AS BIGINT   resolves the error

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From Language DDL  amp  UDF of Hive  NVL value  default value     Returns default value if value is null else returns value

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From  Hive Language Manual  1       COALESCE  T v1  T v2          Will return the first value that is not NULL  or NULL if all values s are NULL  https   cwiki apache org confluence display Hive LanguageManual UDF LanguageManualUDF-ConditionalFunctions

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Since 0 11 hive has a NVL function  nvl T value  T default value   which says      Returns default value if value is null else returns value

User · Answer

Hive supports bigint literal since 0 8 version  So  additional  L  is enough   COALESCE column  0L

[sql] COALESCE with Hive SQL

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