E021-01, “CHARACTER data type (including all its spellings)”

1. Non-standard alternatives available

The fixed-length character string type of SQL is character, the shorter char is a synonym.

CREATE TABLE … (
  currency CHAR(3)
)

The character type can be parameterized to set its length—like 3 in the example. Note that the unit are characters, not bytes.✓✗ In absence of the length, the length defaults to 1 character.

1. Length limitation not enforced

Values shorter than the length are space-padded at the end to reach the required length. Note that pad space collations cause fixed-length string comparisons to behave similar to variable-length string comparisons.

As the type character stores characters, rather than bytes, the character set and collate clauses may be specified.

Non-Standard Alternatives

1. Note that bpchar (without length) is a variable-length string
2. Length limitation not enforced

Related

Supplementary Features

• T062, “Character length units”

Mandatory Features

• E021-02, “CHARACTER VARYING data type (including all its spellings)”

Optional Features

• F421, “National character”

• T046, “CLOB data type”

  • T043, “Multiplier T”

  • T044, “Multiplier P”

• T062, “Character length units”

• T081, “Optional string types maximum length”

Implementation-defined Elements

• IL042, “The maximum lengths for character string types and binary string types.”

Normative References

The SQL types character and char are defined in ISO/IEC 9075-2:2023 as mandatory feature E021-01, “CHARACTER data type (including all its spellings)”. They were already available in SQL-92 (entry level).