Release Notes
- v2.5
- v2.4
- v2.3
- v2.2
- v2.1
- v2.0
- v1.19

StarRocks
Introduction to StarRocks
Quick Start
Table Design
- Understand StarRocks table design
- Data models
- Data distribution
  - Data distribution
  - Dynamic partitioning
- Data compression
- Sort keys and prefix indexes
Data Loading
Data Unloading
Query Data Sources
Query Acceleration
- Gather CBO statistics
- Synchronous materialized view
- Asynchronous materialized view
- Colocate Join
- Lateral Join
- Query Cache
- Index
  - Bitmap indexing
  - Bloom filter indexing
- Computing the Number of Distinct Values
  - Use Bitmap for exact count distinct
  - Use HLL for approximate count distinct
Administration
- Deployment
- Management
- Data recovery
- User Privilege and Authentication
  - User privilege
  - Authentication
- Performance Tuning
Reference
- SQL Reference
- Function Reference
  - Java UDFs
  - Window functions
  - Lambda expression
  - Aggregate Functions
    - avg
    - any_value
    - approx_count_distinct
    - bitmap
    - count
    - grouping
    - grouping_id
    - hll_empty
    - hll_hash
    - hll_union
    - hll_union_agg
    - max
    - max_by
    - min
    - multi_distinct_sum
    - multi_distinct_count
    - percentile_approx
    - percentile_cont
    - retention
    - stddev
    - stddev_samp
    - sum
    - variance, variance_pop, var_pop
    - var_samp
    - window_funnel
  - Array Functions
    - array_agg
    - array_append
    - array_avg
    - array_concat
    - array_contains
    - array_contains_all
    - array_cum_sum
    - array_difference
    - array_distinct
    - array_filter
    - array_intersect
    - array_join
    - array_length
    - array_map
    - array_max
    - array_min
    - array_position
    - array_remove
    - array_slice
    - array_sort
    - array_sortby
    - array_sum
    - arrays_overlap
    - array_to_bitmap
    - reverse
    - unnest
  - Bit Functions
    - bitand
    - bitnot
    - bitor
    - bitxor
    - bit_shift_left
    - bit_shift_right
    - bit_shift_right_logical
  - Bitmap Functions
    - base64_to_bitmap
    - bitmap_and
    - bitmap_andnot
    - bitmap_contains
    - bitmap_count
    - bitmap_from_string
    - bitmap_empty
    - bitmap_has_any
    - bitmap_hash
    - bitmap_intersect
    - bitmap_max
    - bitmap_min
    - bitmap_or
    - bitmap_remove
    - bitmap_to_array
    - bitmap_to_base64
    - bitmap_to_string
    - bitmap_union
    - bitmap_union_count
    - bitmap_union_int
    - bitmap_xor
    - intersect_count
    - sub_bitmap
    - to_bitmap
  - Conditional Functions
    - coalesce
    - if
    - ifnull
    - nullif
  - Cryptographic Functions
    - aes_encrypt
    - aes_decrypt
    - from_base64
    - md5
    - md5sum
    - md5sum_numeric
    - sha2
    - sm3
    - to_base64
  - Date Functions
    - add_months
    - adddate
    - convert_tz
    - current_date
    - current_time
    - current_timestamp
    - date
    - date_add
    - date_format
    - date_slice
    - date_sub, subdate
    - date_trunc
    - datediff
    - day
    - dayname
    - dayofmonth
    - dayofweek
    - dayofyear
    - days_add
    - days_diff
    - days_sub
    - from_days
    - from_unixtime
    - hour
    - hours_sub
    - microseconds_sub
    - minute
    - minutes_add
    - minutes_diff
    - minutes_sub
    - month
    - monthname
    - months_add
    - months_diff
    - now
    - quarter
    - second
    - seconds_add
    - seconds_diff
    - seconds_sub
    - str_to_date
    - str2date
    - time_slice
    - time_to_sec
    - timediff
    - timestamp
    - timestampadd
    - timestampdiff
    - to_date
    - to_days
    - unix_timestamp
    - utc_timestamp
    - week
    - weekofyear
    - weeks_add
    - weeks_diff
    - weeks_sub
    - year
    - years_add
    - years_diff
    - years_sub
  - Geographic Functions
    - st_astext
    - st_circle
    - st_contains
    - st_distance_sphere
    - st_geometryfromtext
    - st_linefromtext
    - st_point
    - st_polygon
    - st_x
    - st_y
  - JSON Functions
    - Overview of JSON functions and operators
    - JSON operators
    - JSON constructor functions
    - JSON query and processing functions
  - Map Functions
    - map_from_arrays
    - map_keys
    - map_size
    - map_values
  - Math Functions
    - abs
    - acos
    - asin
    - atan
    - atan2
    - bin
    - ceil
    - ceiling
    - conv
    - cos
    - cosh
    - cot
    - degrees
    - divide
    - e
    - exp
    - floor
    - fmod
    - greatest
    - least
    - ln
    - log
    - log2
    - log10
    - mod
    - multiply
    - negative
    - pi
    - pmod
    - positive
    - pow
    - radians
    - rand
    - round
    - sign
    - sin
    - sinh
    - sqrt
    - square
    - tan
    - tanh
    - truncate
  - String Functions
    - append_trailing_char_if_absent
    - ascii
    - char
    - char_length
    - character_length
    - concat
    - concat_ws
    - ends_with
    - find_in_set
    - group_concat
    - hex
    - instr
    - lcase
    - left
    - length
    - locate
    - lower
    - lpad
    - ltrim
    - money_format
    - null_or_empty
    - parse_url
    - repeat
    - reverse
    - right
    - rpad
    - rtrim
    - space
    - split
    - split_part
    - starts_with
    - strleft
    - strright
    - substring
    - trim
    - ucase
    - unhex
    - upper
  - Pattern Matching Functions
    - like
    - regexp
    - regexp_extract
    - regexp_replace
  - Percentile Functions
    - percentile_approx_raw
    - percentile_empty
    - percentile_hash
    - percentile_union
  - Scalar Functions
    - hll_cardinality
  - Utility Functions
    - current_version
    - host_name
    - isnull
    - last_query_id
    - sleep
    - uuid
    - uuid_numeric
    - version
  - cast function
  - hash function
- System variables
- User-defined variables
- Error code
- System limits
FAQ
- Deploy
- Data Migration
  - Data Loading
  - Data Unloading
- SQL
- Query Dump
- Other FAQs
Benchmark
- SSB Benchmark
- TPC-H Benchmark

Developers
- Contribute to StarRocks
- Code Style Guides
  - protobuf style guides
  - thrift style guides
- Use the debuginfo file for debugging
- Development Environment
- Trace Tools
  - Trace
Integration
- Integrate with StarRocks
- Authenticate to AWS resources

Edit

map_from_arrays

Description

Creates a MAP value from the given pair of key item array and value item array.

Syntax

MAP map_from_arrays(ARRAY keys, ARRAY values)

Parameters

keys: uses to construct the keys of the result MAP. Make sure the elements of keys are unique.
values: used to construct the values of the result MAP.

Return value

Returns a MAP that is constructed from the input keys and values.

keys and values must have the same length, otherwise it will return an error. If keys or values are NULL, this function will return NULL.

Examples

select map_from_arrays([1, 2], ['Star', 'Rocks']);
+--------------------------------------------+
| map_from_arrays([1, 2], ['Star', 'Rocks']) |
+--------------------------------------------+
| {1:"Star",2:"Rocks"}                       |
+--------------------------------------------+

select map_from_arrays([1, 2], NULL);
+-------------------------------+
| map_from_arrays([1, 2], NULL) |
+-------------------------------+
| NULL                          |
+-------------------------------+

Edit

In this article

map_from_arrays