Drill Mole Mac OS

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Drill reads from and writes to data sources having a wide variety of types.

SQL Data TypeDescriptionExample
BIGINT8-byte signed integer in the range -9,223,372,036,854,775,808 to 9,223,372,036,854,775,8079223372036854775807
BINARYVariable-length byte stringB@e6d9eb7
BOOLEANTrue or falsetrue
DATEYears, months, and days in YYYY-MM-DD format since 4713 BC2015-12-30
DECIMAL(p,s), or DEC(p,s), NUMERIC(p,s)*38-digit precision number, precision is p, and scale is sDECIMAL(6,2) is 1234.56, 4 digits before and 2 digits after the decimal point
FLOAT4-byte floating point number0.456
DOUBLE, DOUBLE PRECISION8-byte floating point number, precision-scalable0.456
INTEGER or INT4-byte signed integer in the range -2,147,483,648 to 2,147,483,6472147483646
INTERVAL**A day-time or year-month interval‘1 10:20:30.123' (day-time) or ‘1-2' year to month (year-month)
SMALLINT***2-byte signed integer in the range -32,768 to 32,76732000
TIME24-hour based time before or after January 1, 2001 in hours, minutes, seconds format: HH:mm:ss22:55:55.23
TIMESTAMPJDBC timestamp in year, month, date hour, minute, second, and optional milliseconds format: yyyy-MM-dd HH:mm:ss.SSS2015-12-30 22:55:55.23
CHARACTER VARYING, CHARACTER, CHAR,** or VARCHARUTF8-encoded variable-length string. The default limit is 1 character. The maximum character limit is 2,147,483,647.CHAR(30) casts data to a 30-character string maximum.

* Starting in Drill 1.14, the DECIMAL data type is enabled by default.
** Internally, INTERVAL is represented as INTERVALDAY or INTERVALYEAR.
*** SMALLINT is not currently supported.
**** The CHAR data type is internally represented as VARCHAR by Drill.

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DECIMAL Data Type

Starting in Drill 1.14, DECIMAL data type support is enabled by default. Drill uses the vardecimal data type to store decimal and numeric data types in a compressed format that optimizes storage space. The vardecimal data type stores decimal and numeric values as variable length columns that can represent any decimal precision.

In Drill, the SQL DECIMAL and NUMERIC data types map to the java.math.BigDecimal Java data type.

Syntax

The DECIMAL data type accepts numeric values, for which you can define a precision and a scale, as shown:

Precision is an integer that indicates how many digits the number will contain. Scale is an integer that indicates the number of digits to the right of the decimal point. For example, the number 2325.67 has a precision of 6 and scale of 2. In a query, DECIMAL (6,2).

Scale cannot be greater than the precision. If you do not indicate a precision or scale, the default precision is 38 and scale is 0.

Decimal Data Type Storage Format Support

Drill can read decimal data types from and write decimal data types to the following storage format:

  • parquet

Drill can read decimal data types from the following storage formats, but cannot write decimal data types to them:

  • hive
  • jdbc
  • avro

Decimal Type Options

You can use the SET command with the planner.enable_decimal_data_type option to turn DECIMAL data type support off and on. If you disable the planner.enable_decimal_data_type option (by setting it to false), Drill treats decimal literals as DOUBLE.

Drill 1.14 introduces the following additional decimal-related options for the Parquet storage format that you can modify using the SET command:

  • store.parquet.writer.use_primitive_types_for_decimals (boolean)
    Allows Drill to use INT32 and INT64 logical types when storing decimal values in Parquet if the precision of the value allows it. Default is true. Set to false to prevent Drill from using INT32 and INT64 logical types, as shown:

  • store.parquet.writer.logical_type_for_decimals Indicates the logical type that Drill should use to store decimals. The default is fixed_len_byte_array. Alternatively, you can set this option to binary, as shown:

Composite Types

Drill supports the following composite types:

  • Map
  • Array

A map is a set of name/value pairs. A value in a map can be a scalar type, such as string or int, or a complex type, such as an array or another map. An array is a repeated list of values. A value in an array can be a scalar type, such as string or int, or an array can be a complex type, such as a map or another array.

Drill uses map and array data types internally for reading complex and nested data structures from data sources. In this release of Drill, you cannot reference a composite type by name in a query, but Drill supports array values coming from data sources. For example, you can use the index syntax to query data and get the value of an array element:

a[1]

You can refer to the value for a key in a map using dot notation:

t.m.k

The section 'Query Complex Data' shows how to use composite types to access nested arrays. 'Handling Different Data Types' includes examples of JSON maps and arrays. Drill provides functions for handling array and map types:

ANY Type

The ANY type is a key technological advance in Drill that enables it to address late typing problems. Drill uses the ANY type internally and you might see references to ANY in the output of the DESCRIBE or other commands. You cannot cast a value to the ANY type in this release.

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Using the ANY type, the parser postpones the problem of resolving the type of some value until the query is actually running. At that point, Drill has an empirical schema available for each record batch to use for final codegeneration and optimization. If the empirical schema changes due tochanges in the data processing, Drill regenerates the code as necessary.

Casting and Converting Data Types

In Drill, you cast or convert data to the required type for moving data from one data source to another.You do not assign a data type to every column name in a CREATE TABLE statement to define the table as you do in database software. Instead, you use the CREATE TABLE AS (CTAS) statement with one or more of the following functions to define the table:

  • CONVERT TO/FROM
    Use the CONVERT TO AND CONVERT FROM data types
  • Other data conversion functions

In some cases, Drill converts schema-less data to correctly-typed data implicitly. In this case, you do not need to cast the data. The file format of the data and the nature of your query determines the requirement for casting or converting. Differences in casting depend on the data source. The following list describes how Drill treats data types from various data sources:

  • HBase
    Does not implicitly cast input to SQL types. Convert data to appropriate types as as described in the section 'Querying HBase'. Use CONVERT_TO or CONVERT_FROM data types.
  • Hive
    Implicitly casts Hive types to SQL types as shown in the Hive type mapping example
  • JSON
    Implicitly casts JSON data to its corresponding SQL types or to VARCHAR if Drill is in all text mode.
  • MapR-DB
    Implicitly casts MapR-DB data to SQL types when you use the maprdb format for reading MapR-DB data. The dfs storage plugin defines the format when you install Drill from the mapr-drill package on a MapR node.
  • Parquet
    Implicitly casts Parquet data to the SQL types shown in SQL Data Types to Parquet.
  • Text: CSV, TSV, and other text
    Implicitly casts all textual data to VARCHAR.

Implicit Casting Precedence of Data Types

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The following list includes data types Drill uses in descending order of precedence. Casting precedence shown in the following table applies to the implicit casting that Drill performs. For example, Drill might implicitly cast data when a query includes a function or filter on mismatched data types:

As shown in the table, Drill can cast a NULL value, which has the lowest precedence, to any other type; you can cast a SMALLINT (not supported in this release) value to INT. Drill might deviate from these precedence rules for performance reasons. Under certain circumstances, such as queries involving SUBSTR and CONCAT functions, Drill reverses the order of precedence and allows a cast to VARCHAR from a type of higher precedence than VARCHAR, such as BIGINT. The INTERVALDAY and INTERVALYEAR types are internal types.

Casting Precedence

PrecedenceData TypePrecedenceData Type
1INTERVALYEAR (highest)12UINT2
2INTERVALDAY13SMALLINT*
3TIMESTAMP14UINT1
4DATE15VAR16CHAR
5TIME16FIXED16CHAR
6DOUBLE17VARCHAR
7DECIMAL18CHAR
8UINT819VARBINARY
9BIGINT20FIXEDBINARY
10UINT421NULL (lowest)
11INT

* Not supported in this release.

Explicit Casting

In a textual file, such as CSV, Drill interprets every field as a VARCHAR, as previously mentioned. To handle textual data, you can use the following functions to cast and convert compatible data types:

  • CAST
    Casts data from one data type to another.
  • CONVERT_TO and CONVERT_FROM/docs/data-type-conversion/#convert_to-and-convert_from)Convert data, including binary data, from one data type to another using 'CONVERT_TO and CONVERT_FROM data types'
  • TO_CHAR
    Converts a TIMESTAMP, INTERVALDAY/INTERVALYEAR, INTEGER, DOUBLE, or DECIMAL to a string.
  • TO_DATE
    Converts a string to DATE.
  • TO_NUMBER
    Converts a string to a DECIMAL.
  • TO_TIMESTAMP
    Converts a string to TIMESTAMP.

If the SELECT statement includes a WHERE clause that compares a column of an unknown data type, cast both the value of the column and the comparison value in the WHERE clause.

Explicit Type Casting Maps

The following tables show data types that Drill can cast to/from other data types. Not all types are available for explicit casting in the current release.

Numerical and Character Data Types

ToSMALLINTINTBIGINTDECIMALFLOATCHARFIXEDBINARYVARCHARVARBINARY
From:
SMALLINT*yesyesyesyesyesyesyesyesyes
INTyesyesyesyesyesyesyesyesyes
BIGINTyesyesyesyesyesyesyesyesyes
DECIMALyesyesyesyesyesyesyesyesyes
DOUBLEyesyesyesyesyesyesnoyesno
FLOATyesyesyesyesyesyesnoyesno
CHARyesyesyesyesyesnoyesyesyes
FIXEDBINARY**yesyesyesyesyesnonoyesyes
VARCHAR***yesyesyesyesyesyesyesnoyes
VARBINARY**yesyesyesyesyesnoyesyesno

* Not supported in this release.
** Used to cast binary UTF-8 data coming to/from sources such as HBase.
*** You cannot convert a character string having a decimal point to an INT or BIGINT.

Note

The CAST function does not support all representations of FIXEDBINARY and VARBINARY. Only the UTF-8 format is supported.

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The following list includes data types Drill uses in descending order of precedence. Casting precedence shown in the following table applies to the implicit casting that Drill performs. For example, Drill might implicitly cast data when a query includes a function or filter on mismatched data types:

As shown in the table, Drill can cast a NULL value, which has the lowest precedence, to any other type; you can cast a SMALLINT (not supported in this release) value to INT. Drill might deviate from these precedence rules for performance reasons. Under certain circumstances, such as queries involving SUBSTR and CONCAT functions, Drill reverses the order of precedence and allows a cast to VARCHAR from a type of higher precedence than VARCHAR, such as BIGINT. The INTERVALDAY and INTERVALYEAR types are internal types.

Casting Precedence

PrecedenceData TypePrecedenceData Type
1INTERVALYEAR (highest)12UINT2
2INTERVALDAY13SMALLINT*
3TIMESTAMP14UINT1
4DATE15VAR16CHAR
5TIME16FIXED16CHAR
6DOUBLE17VARCHAR
7DECIMAL18CHAR
8UINT819VARBINARY
9BIGINT20FIXEDBINARY
10UINT421NULL (lowest)
11INT

* Not supported in this release.

Explicit Casting

In a textual file, such as CSV, Drill interprets every field as a VARCHAR, as previously mentioned. To handle textual data, you can use the following functions to cast and convert compatible data types:

  • CAST
    Casts data from one data type to another.
  • CONVERT_TO and CONVERT_FROM/docs/data-type-conversion/#convert_to-and-convert_from)Convert data, including binary data, from one data type to another using 'CONVERT_TO and CONVERT_FROM data types'
  • TO_CHAR
    Converts a TIMESTAMP, INTERVALDAY/INTERVALYEAR, INTEGER, DOUBLE, or DECIMAL to a string.
  • TO_DATE
    Converts a string to DATE.
  • TO_NUMBER
    Converts a string to a DECIMAL.
  • TO_TIMESTAMP
    Converts a string to TIMESTAMP.

If the SELECT statement includes a WHERE clause that compares a column of an unknown data type, cast both the value of the column and the comparison value in the WHERE clause.

Explicit Type Casting Maps

The following tables show data types that Drill can cast to/from other data types. Not all types are available for explicit casting in the current release.

Numerical and Character Data Types

ToSMALLINTINTBIGINTDECIMALFLOATCHARFIXEDBINARYVARCHARVARBINARY
From:
SMALLINT*yesyesyesyesyesyesyesyesyes
INTyesyesyesyesyesyesyesyesyes
BIGINTyesyesyesyesyesyesyesyesyes
DECIMALyesyesyesyesyesyesyesyesyes
DOUBLEyesyesyesyesyesyesnoyesno
FLOATyesyesyesyesyesyesnoyesno
CHARyesyesyesyesyesnoyesyesyes
FIXEDBINARY**yesyesyesyesyesnonoyesyes
VARCHAR***yesyesyesyesyesyesyesnoyes
VARBINARY**yesyesyesyesyesnoyesyesno

* Not supported in this release.
** Used to cast binary UTF-8 data coming to/from sources such as HBase.
*** You cannot convert a character string having a decimal point to an INT or BIGINT.

Note

The CAST function does not support all representations of FIXEDBINARY and VARBINARY. Only the UTF-8 format is supported.

If your FIXEDBINARY or VARBINARY data is in a format other than UTF-8, or big-endian encoded, use the CONVERT_TO/FROM functions instead of CAST.

Date and Time Data Types

To:DATETIMETIMESTAMPINTERVALYEARINTERVALDAY
From:
CHARYesYesYesYesYes
FIXEDBINARY*NoNoNoNoNo
VARCHARYesYesYesYesYes
VARBINARY*NoNoYesNoNo
DATENoNoYesNoNo
TIMENoYesYesNoNo
TIMESTAMPYesYesYesNoNo
INTERVALYEARYesNoYesNoYes
INTERVALDAYYesNoYesYesNo

* Used to cast binary UTF-8 data coming to/from sources such as HBase. The CAST function does not support all representations of FIXEDBINARY and VARBINARY. Only the UTF-8 format is supported.

Data Types for CONVERT_TO and CONVERT_FROM Functions

The CONVERT_TO function converts data to bytes from the input type. The CONVERT_FROM function converts data from bytes to the input type. For example, the following CONVERT_TO function converts an integer to bytes using big endian encoding:

The following table lists the data types you can use with the CONVERT_TOand CONVERT_FROM functions:

TypeInput TypeOutput Type
JSONbytesvarchar
BOOLEAN_BYTEbytes(1)BOOLEAN
TINYINT_BEbytes(1)TINYINT
TINYINTbytes(1)TINYINT
SMALLINT_BEbytes(2)SMALLINT
SMALLINTbytes(2)SMALLINT
INT_BEbytes(4)INT
INTbytes(4)INT
BIGINT_BEbytes(8)BIGINT
BIGINTbytes(8)BIGINT
FLOATbytes(4)FLOAT (float4)
DOUBLEbytes(8)DOUBLE (float8)
INT_HADOOPVbytes(1-9)INT
BIGINT_HADOOPVBYTES(1-9)BIGINT
DATE_EPOCH_BEbytes(8)DATE
DATE_EPOCHbytes(8)DATE
TIME_EPOCH_BEbytes(8)TIME
TIME_EPOCHbytes(8)TIME
TIMESTAMP_EPOCHbytes(8)TIMESTAMP
TIMESTAMP_IMPALA*bytes(12)TIMESTAMP
UTF8bytesVARCHAR
UTF16bytesVAR16CHAR
UINT8bytes(8)UINT8
UINT8_BEbytes(8)UINT8

* In Drill 1.2 and later, use the TIMESTAMP_IMPALA type with the CONVERT_FROM function to decode a timestamp from Hive or Impala, as shown in the section, 'About INT96 Support'.

This table includes types such as INT, for converting little endian-encoded data and types such as INT_BE for converting big endian-encoded data to Drill internal types. You need to convert binary representations, such as data in HBase, to a Drill internal format as you query the data. If you are unsure that the size of the source and destination INT or BIGINT you are converting is the same, use CAST to convert these data types to/from binary.

*_HADOOPV in the data type name denotes the variable length integer as defined by Hadoop libraries. Use a *_HADOOPV type if user data is encoded in this format by a Hadoop tool outside MapR.

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