D.1. Supported Features # Identifier Core? Description Comment B012 Embedded C B021 Direct SQL B128 Routine language SQL E011 Core Numeric data types E011-01 Core INTEGER and SMALLINT data types E011-02 Core REAL, DOUBLE PRECISION, and FLOAT data types E011-03 Core DECIMAL and NUMERIC data types E011-04 Core Arithmetic operators E011-05 Core Numeric comparison E011-06 Core Implicit casting among the numeric data types E021 Core Character data types E021-01 Core CHARACTER data type E021-02 Core CHARACTER VARYING data type E021-03 Core Character literals E021-04 Core CHARACTER_LENGTH function trims trailing spaces from CHARACTER values before counting E021-05 Core OCTET_LENGTH function E021-06 Core SUBSTRING function E021-07 Core Character concatenation E021-08 Core UPPER and LOWER functions E021-09 Core TRIM function E021-10 Core Implicit casting among the character string types E021-11 Core POSITION function E021-12 Core Character comparison E031 Core Identifiers E031-01 Core Delimited identifiers E031-02 Core Lower case identifiers E031-03 Core Trailing underscore E051 Core Basic query specification E051-01 Core SELECT DISTINCT E051-02 Core GROUP BY clause E051-04 Core GROUP BY can contain columns not in