Skip to content

SQL helpers for string functions

Source: R/translate-sql-string.R
sql_translation_string.Rd

These functions help you create custom string SQL translations when implementing a new backend. They are typically used within sql_translator() to define how R string functions should be translated to SQL.

  • sql_substr() creates a SQL substring function translator that converts R's substr(x, start, stop) to SQL's SUBSTR(x, start, length).

  • sql_str_sub() creates a SQL substring function translator that handles stringr's str_sub() with support for negative indices.

  • sql_paste() creates a SQL paste function using CONCAT_WS() or similar.

  • sql_paste_infix() creates a SQL paste function using an infix operator like ||.

Usage

sql_substr(f = "SUBSTR")

sql_str_sub(subset_f = "SUBSTR", length_f = "LENGTH", optional_length = TRUE)

sql_paste(default_sep, f = "CONCAT_WS")

sql_paste_infix(default_sep, op, cast = sql_cast("text"))

Arguments

f

The name of the SQL function as a string.

subset_f

The name of the SQL substring function.

length_f

The name of the SQL string length function.

optional_length

Whether the length argument is optional in the SQL substring function.

default_sep

The default separator for paste operations.

op

The SQL operator to use for infix paste operations.

cast

A function to cast values to strings.

See also

Other SQL translation helpers: sql_translation_agg, sql_translation_scalar, sql_translation_window, sql_variant()