Annotate a query with inferred data types — sql_annotate

Runs upstream type inference over the AST. With a schema, column references resolve to their declared types; without one, only types that can be inferred from literals, casts and function signatures are filled.

Usage

sql_annotate_types(sql, dialect = "generic", schema = NULL)

Arguments

sql: A single character string with one or more SQL statements (separated by ;).
dialect: Dialect used for parsing.
schema: Optional schema specification (see as_polyglot_schema()); improves resolution of unqualified or ambiguous columns.

Value

A polyglot_ast object whose nodes carry an inferred_type field where a type could be determined. Pass it to sql_generate() to render, or inspect $statements directly.

Examples

ast <- sql_annotate_types(
  "SELECT id + 1 AS next_id FROM t",
  schema = list(t = c(id = "INT"))
)
# the Add node now carries inferred_type INT