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Text Types

In DuckDB, strings can be stored in the VARCHAR field.

Name Aliases Description
VARCHAR CHAR, BPCHAR, TEXT, STRING variable-length character string
VARCHAR(n)   variable-length character string with maximum length n

It is possible to supply a number along with the type by initializing a type as VARCHAR(n), where n is a positive integer. Note that specifying this length is not required and has no effect on the system. Specifying this length will not improve performance or reduce storage space of the strings in the database. This variant is supported for compatibility reasons with other systems that do require a length to be specified for strings.

If you wish to restrict the number of characters in a VARCHAR column for data integrity reasons the CHECK constraint should be used, for example:

CREATE TABLE strings(
    val VARCHAR CHECK(LENGTH(val) <= 10) -- val has a maximum length of 10 characters
);

The VARCHAR field allows storage of Unicode characters. Internally, the data is encoded as UTF-8.

Formatting Strings

Strings in DuckDB are surrounded by single quote (apostrophe) characters ('):

SELECT 'Hello world' AS msg;

┌─────────────┐
│     msg     │
│   varchar   │
├─────────────┤
│ Hello world │
└─────────────┘

To include a single quote character in a string, use '':

SELECT 'Hello ''world''' AS msg;

┌───────────────┐
│      msg      │
│    varchar    │
├───────────────┤
│ Hello 'world' │
└───────────────┘

To include special characters such as newline, use the chr character function:

SELECT 'Hello' || chr(10) || 'world' AS msg;

┌──────────────┐
│     msg      │
│   varchar    │
├──────────────┤
│ Hello\nworld │
└──────────────┘

Double Quote Characters

Double quote characters (") are used to denote table and column names. Surrounding their names allows the use of keywords, e.g.:

CREATE TABLE "table"("order" BIGINT);

While DuckDB occasionally accepts both single quote and double quotes for strings (e.g., both FROM "filename.csv" and FROM 'filename.csv' work), their use is not recommended.

Functions

See Character Functions and Pattern Matching.

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