Hive complex type access operation

Complex type access operation 1. Array type access: a [n]

Syntax: a [n]

Operation type: an is array type, n is int type

Description: returns the nth variable value in array A. The starting subscript of the array is 0. For example, if An is an array type with a value of ['foo',' bar'], then A [0] will return 'foo',' and A [1] will return 'bar''

For example:

Hive > create table lxw_test as selectarray ("tom", "mary", "tim") as t from lxw_dual

Hive > select t [0], t [1], t [2] from lxw_test

Tom mary tim

2. Map type access: M [key]

Syntax: M [key]

Operation type: M is the map type, and key is the key value in map

Description: returns the map type M where the key value is the value of the specified value. For example, if M is a map type with a value of {'f'- > 'foo',' bounded-> 'bar',' all'-> 'foobar'}, then M [' all'] will return 'foobar''

For example:

Hive > Create table lxw_test as selectmap ('100th and 2000s) as t from lxw_dual

Hive > select t ['200'], t [' 100'] from lxw_test

Mary tom

3. Struct type access: S.X

Syntax: S.X

Operation type: s is struct type

Description: returns the x field in structure S. For example, for the structure struct foobar {int foo, int bar}, foobar.foo returns the foo field in the structure

For example:

Hive > create table lxw_test as select struct ('tom','mary','tim') as t from lxw_dual

Hive > describe lxw_test

T struct

Hive > select t.col1mt. Col3 from lxw_test

Tom tim

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