Character

Updated on 2022-11-18 GMT+08:00

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Name	Description
VARCHAR(n)	Variable-length character string. n indicates the byte length.
CHAR(n)	Fixed-length character string. If the length is insufficient, spaces are added. n indicates the byte length. If the precision n is not specified, the default value 1 is used.
VARBINARY	Variable-length binary data. The value must be prefixed with X, for example, X'65683F'. Currently, a binary character string of a specified length is not supported.
JSON	The value can be a JSON object, a JSON array, a JSON number, a JSON string, true, false or null.
STRING	String compatible with impala. The bottom layer is varchar.
BINARY	Compatible with Hive BINARY. The underlying implementation is VARBINARY.

In SQL expressions, simple character expressions and unicodes are supported. A unicode character string uses U& as the fixed prefix. An escape character must be added before Unicode that is represented by a 4-digit value.

VARBINARY and BINARY

-- Creating a VARBINARY or BINARY Table
 create table binary_tb(col1 BINARY);

--Insert data.
 INSERT INTO binary_tb values (X'63683F');

--Query data.
 select * from binary_tb ;  -- 63 68 3f

When two CHARs with different numbers of spaces at the end are compared, the two CHARs are considered equal.
```
SELECT CAST('FO' AS CHAR(4)) = CAST('FO     ' AS CHAR(5));
 _col0 
-------
 true  
(1 row)
```