diff --git a/concepts/Readme.md b/concepts/Readme.md
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+# MIMIC-IV Concepts
+
+## Generating the concepts in PostgreSQL (*nix/Mac OS X)
+
+Analogously to [MIMIC-III Concepts](https://github.com/MIT-LCP/mimic-code/tree/master/concepts), the SQL scripts here are written in BigQuery's Standard SQL syntax, so that the following changes are necessary to make them compaible with PostgreSQL:
+
+* create postgres functions which emulate BigQuery functions (identical to MIMIC-III)
+* modify SQL scripts for incompatible syntax
+* run the modified SQL scripts and direct the output into tables in the PostgreSQL database
+
+This can be done as follows (again, analogously to [MIMIC-III](https://github.com/MIT-LCP/mimic-code/tree/master/concepts):
+
+1. Open a terminal in the `concepts` folder.
+2. Run [postgres-functions.sql](postgres-functions.sql).
+    * e.g. `psql -f postgres-functions.sql`
+    * This script creates functions which emulate BigQuery syntax.
+3. Run [postgres_make_concepts.sh](postgres_make_concepts.sh).
+    * e.g. `bash postgres_make_concepts.sh`
+    * This file runs the scripts after applying a few regular expressions which convert table references and date calculations appropriately.
+    * This file generates all concepts on the `public` schema.
+
+The main difference to MIMIC-III are different slightly different regular expressions and a loop similar to [make_concepts.sh](make_concepts.sh). Also, one of them uses `perl` now, which might be necessary to install.
+
+### Known Problems
+
+* [postgres_make_concepts.sh](postgres_make_concepts.sh) fails for [icustays_hourly.sh](demographics/icustays_hourly.sh) due to `INTERVAL CAST(hr AS INT64) HOUR)', which cannot easily be changed into a PostrgeSQL compatible expression.
diff --git a/concepts/postgres-functions.sql b/concepts/postgres-functions.sql
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+-- Functions TODO:
+--  FROM table CROSS JOIN UNNEST(table.column) AS col -> ????  (see icustay-hours)
+--  ???(column) -> PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY column)    (not sure how to do median in BQ)
+
+SET search_path TO public;
+
+CREATE OR REPLACE FUNCTION REGEXP_EXTRACT(str TEXT, pattern TEXT) RETURNS TEXT AS $$
+BEGIN
+RETURN substring(str from pattern);
+END; $$
+LANGUAGE PLPGSQL;
+
+CREATE OR REPLACE FUNCTION REGEXP_CONTAINS(str TEXT, pattern TEXT) RETURNS BOOL AS $$
+BEGIN
+RETURN str ~ pattern;
+END; $$
+LANGUAGE PLPGSQL;
+
+-- alias generate_series with generate_array
+CREATE OR REPLACE FUNCTION GENERATE_ARRAY(i INTEGER, j INTEGER)
+RETURNS setof INTEGER language sql as $$
+    SELECT GENERATE_SERIES(i, j)
+$$;
+
+-- datetime functions
+CREATE OR REPLACE FUNCTION DATETIME(dt DATE) RETURNS TIMESTAMP(3) AS $$
+BEGIN
+RETURN CAST(dt AS TIMESTAMP(3));
+END; $$
+LANGUAGE PLPGSQL;
+
+CREATE OR REPLACE FUNCTION DATETIME(year INTEGER, month INTEGER, day INTEGER, hour INTEGER, minute INTEGER, second INTEGER) RETURNS TIMESTAMP(3) AS $$
+BEGIN
+RETURN TO_TIMESTAMP(
+    TO_CHAR(year, '0000') || TO_CHAR(month, '00') || TO_CHAR(day, '00') || TO_CHAR(hour, '00') || TO_CHAR(minute, '00') || TO_CHAR(second, '00'),
+    'yyyymmddHH24MISS'
+);
+END; $$
+LANGUAGE PLPGSQL;
+
+-- overload allowing string input
+
+--  DATETIME_ADD(datetime, INTERVAL 'n' DATEPART) -> datetime + INTERVAL 'n' DATEPART
+-- note: in bigquery, `INTERVAL 1 YEAR` is a valid interval
+-- but in postgres, it must be `INTERVAL '1' YEAR`
+CREATE OR REPLACE FUNCTION DATETIME_ADD(datetime_val TIMESTAMP(3), intvl INTERVAL) RETURNS TIMESTAMP(3) AS $$
+BEGIN
+RETURN datetime_val + intvl;
+END; $$
+LANGUAGE PLPGSQL;
+
+--  DATETIME_SUB(datetime, INTERVAL 'n' DATEPART) -> datetime - INTERVAL 'n' DATEPART
+CREATE OR REPLACE FUNCTION DATETIME_SUB(datetime_val TIMESTAMP(3), intvl INTERVAL) RETURNS TIMESTAMP(3) AS $$
+BEGIN
+RETURN datetime_val - intvl;
+END; $$
+LANGUAGE PLPGSQL;
+
+-- TODO:
+--   DATETIME_TRUNC(datetime, PART) -> DATE_TRUNC('datepart', datetime)
+
+-- below requires a regex to convert datepart from primitive to a string
+-- i.e. encapsulate it in single quotes
+CREATE OR REPLACE FUNCTION DATETIME_DIFF(endtime TIMESTAMP(3), starttime TIMESTAMP(3), datepart TEXT) RETURNS NUMERIC AS $$
+BEGIN
+RETURN 
+    EXTRACT(EPOCH FROM endtime - starttime) /
+    CASE
+        WHEN datepart = 'SECOND' THEN 1.0
+        WHEN datepart = 'MINUTE' THEN 60.0
+        WHEN datepart = 'HOUR' THEN 3600.0
+        WHEN datepart = 'DAY' THEN 24*3600.0
+        WHEN datepart = 'YEAR' THEN 365.242*24*3600.0
+    ELSE NULL END;
+END; $$
+LANGUAGE PLPGSQL;
+
+-- BigQuery has a custom data type, PART
+-- It's difficult to replicate this in postgresql, which recognizes the PART as a column name,
+-- unless it is within an EXTRACT() function.
+
+CREATE OR REPLACE FUNCTION BIGQUERY_FORMAT_TO_PSQL(format_str VARCHAR(255)) RETURNS TEXT AS $$
+BEGIN
+RETURN 
+    -- use replace to convert BigQuery string format to postgres string format
+    -- only handles a few cases since we don't extensively use this function
+    REPLACE(
+    REPLACE(
+    REPLACE(
+    REPLACE(
+    REPLACE(
+    REPLACE(
+        format_str
+        , '%S', 'SS'
+    )
+        , '%M', 'MI'
+    )
+        , '%H', 'HH24'
+    )
+        , '%d', 'dd'
+    )
+        , '%m', 'mm'
+    )
+        , '%Y', 'yyyy'
+    )
+;
+END; $$
+LANGUAGE PLPGSQL;
+
+
+CREATE OR REPLACE FUNCTION FORMAT_DATE(format_str VARCHAR(255), datetime_val TIMESTAMP(3)) RETURNS TEXT AS $$
+BEGIN
+RETURN TO_CHAR(
+    datetime_val,
+    -- use replace to convert BigQuery string format to postgres string format
+    -- only handles a few cases since we don't extensively use this function
+    BIGQUERY_FORMAT_TO_PSQL(format_str)
+);
+END; $$
+LANGUAGE PLPGSQL;
+
+
+CREATE OR REPLACE FUNCTION PARSE_DATE(format_str VARCHAR(255), string_val VARCHAR(255)) RETURNS DATE AS $$
+BEGIN
+RETURN TO_DATE(
+    string_val,
+    -- use replace to convert BigQuery string format to postgres string format
+    -- only handles a few cases since we don't extensively use this function
+    BIGQUERY_FORMAT_TO_PSQL(format_str)
+);
+END; $$
+LANGUAGE PLPGSQL;
+
+CREATE OR REPLACE FUNCTION FORMAT_DATETIME(format_str VARCHAR(255), datetime_val TIMESTAMP(3)) RETURNS TEXT AS $$
+BEGIN
+RETURN TO_CHAR(
+    datetime_val,
+    -- use replace to convert BigQuery string format to postgres string format
+    -- only handles a few cases since we don't extensively use this function
+    BIGQUERY_FORMAT_TO_PSQL(format_str)
+);
+END; $$
+LANGUAGE PLPGSQL;
+
+
+CREATE OR REPLACE FUNCTION PARSE_DATETIME(format_str VARCHAR(255), string_val VARCHAR(255)) RETURNS TIMESTAMP(3) AS $$
+BEGIN
+RETURN TO_TIMESTAMP(
+    string_val,
+    -- use replace to convert BigQuery string format to postgres string format
+    -- only handles a few cases since we don't extensively use this function
+    BIGQUERY_FORMAT_TO_PSQL(format_str)
+);
+END; $$
+LANGUAGE PLPGSQL;
+
+
diff --git a/concepts/postgres_make_concepts.sh b/concepts/postgres_make_concepts.sh
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+#!/bin/bash
+# This file makes tables for the concepts in this subfolder.
+# Be sure to run postgres-functions.sql first, as the concepts rely on those function definitions.
+# Note that this may take a large amount of time and hard drive space.
+
+# string replacements are necessary for some queries
+export REGEX_DATETIME_DIFF="s/DATETIME_DIFF\((.+?),\s?(.+?),\s?(DAY|MINUTE|SECOND|HOUR|YEAR)\)/DATETIME_DIFF(\1, \2, '\3')/g"
+export REGEX_SCHEMA='s/`physionet-data.(mimic_core|mimic_icu|mimic_derived|mimic_hosp).(.+?)`/\1.\2/g'
+# Add necessary quotes to INTERVAL, e.g. "INTERVAL 5 hour" to "INTERVAL '5' hour"
+export REGEX_INTERVAL="s/interval\s([[:digit:]])\s(hour|day|month|year)/INTERVAL '\1' \2/gI"
+# Add numeric cast to ROUND(), e.g. "ROUND(1.234, 2)" to "ROUND( CAST(1.234 as numeric), 2)" over 0 or 3 lines
+export PERL_REGEX_ROUND='s/round\((.*|.*[\n]?.*[\n]?.*[\n]?.*)(\, \d\))/ROUND\( CAST\($1 as numeric\)$2/gi'
+export CONNSTR='-d mimic'
+
+# this is set as the search_path variable for psql
+# a search path of "public,mimic_icu" will search both public and mimic_icu
+# schemas for data, but will create tables on the public schema
+export PSQL_PREAMBLE='SET search_path TO public,mimic_icu'
+export TARGET_DATASET='mimic_derived'
+
+echo ''
+echo '==='
+echo 'Beginning to create tables for MIMIC database.'
+echo 'Any notices of the form "NOTICE: TABLE "XXXXXX" does not exist" can be ignored.'
+echo 'The scripts drop views before creating them, and these notices indicate nothing existed prior to creating the view.'
+echo '==='
+echo ''
+
+# generate tables in subfolders
+# for d in demographics measurement medication treatment firstday score;
+for d in firstday;
+do
+    for fn in `ls $d`;
+    do
+        echo "${d}"
+        # only run SQL queries
+        if [[ "${fn: -4}" == ".sql" ]]; then
+            # table name is file name minus extension
+            tbl="${fn::-4}"
+
+            # skip first_day_sofa as it depends on other firstday queries
+            if [[ "${tbl}" == "first_day_sofa" ]]; then
+                continue
+            fi
+            echo "Generating ${TARGET_DATASET}.${tbl}"
+            { echo "${PSQL_PREAMBLE}; DROP TABLE IF EXISTS ${TARGET_DATASET}.${tbl}; CREATE TABLE ${TARGET_DATASET}.${tbl} AS "; cat "${d}/${fn}";} | sed -r -e "${REGEX_DATETIME_DIFF}" | sed -r -e "${REGEX_SCHEMA}" | sed -r -e "${REGEX_INTERVAL}" | perl -0777 -pe "${PERL_REGEX_ROUND}" |  psql ${CONNSTR}
+        fi
+    done
+done
+
+
+# generate first_day_sofa table last
+echo "Generating ${TARGET_DATASET}.first_day_sofa"
+{ echo "${PSQL_PREAMBLE}; DROP TABLE IF EXISTS ${TARGET_DATASET}.first_day_sofa; CREATE TABLE ${TARGET_DATASET}.first_day_sofa AS "; cat firstday/first_day_sofa.sql;} | sed -r -e "${REGEX_DATETIME_DIFF}" | sed -r -e "${REGEX_SCHEMA}" | sed -r -e "${REGEX_INTERVAL}" | perl -0777 -pe "${PERL_REGEX_ROUND}" |  psql ${CONNSTR}