diff --git a/src/drivers/snowflake/rename_functions.rs b/src/drivers/snowflake/rename_functions.rs
index a14ff4f..0ffb875 100644
--- a/src/drivers/snowflake/rename_functions.rs
+++ b/src/drivers/snowflake/rename_functions.rs
@@ -9,6 +9,7 @@ use crate::ast::{FunctionName, Identifier};
 // A `phf_map!` of BigQuery function names to Snowflake function names. Use
 // this for simple renaming.
 static FUNCTION_NAMES: phf::Map<&'static str, &'static str> = phf::phf_map! {
+    "GENERATE_UUID" => "UUID_STRING",
     "REGEXP_EXTRACT" => "REGEXP_SUBSTR",
     "SHA256" => "SHA2_BINARY", // Second argument defaults to SHA256.
 };
@@ -32,6 +33,7 @@ impl Udf {
 /// A `phf_map!` of BigQuery UDF names to Snowflake UDFs. Use this when we
 /// actually need to create a UDF as a helper function.
 static UDFS: phf::Map<&'static str, &'static Udf> = phf::phf_map! {
+    "RAND" => &Udf { decl: "RAND() RETURNS FLOAT", sql: "UNIFORM(0::float, 1::float, RANDOM())" },
     "TO_HEX" => &Udf { decl: "TO_HEX(b BINARY) RETURNS STRING", sql: "HEX_ENCODE(b, 0)" },
 };
 
diff --git a/tests/sql/functions/README.md b/tests/sql/functions/README.md
index f0a3b55..9708926 100644
--- a/tests/sql/functions/README.md
+++ b/tests/sql/functions/README.md
@@ -18,36 +18,41 @@ generate your own version of this list by running `joinery parse
 - [x] LENGTH(_)
 - [x] CONCAT(*)
 - [x] TRIM(_)
-- [ ] ARRAY_TO_STRING(_,_)
 - [x] SUM(_)
 - [x] FARM_FINGERPRINT(_)
-- [ ] ANY_VALUE(_)
-- [ ] ROW_NUMBER() OVER(..)
-- [ ] COUNTIF(_)
+- [x] ANY_VALUE(_)
+- [x] ROW_NUMBER() OVER(..)
+- [x] COUNTIF(_)
 - [x] UPPER(_)
-- [ ] ARRAY_AGG(_)
-- [ ] DATE_TRUNC(_,_) (special)
 - [x] MIN(_)
-- [ ] FORMAT_DATETIME(_,_)
-- [ ] RAND()
-- [ ] RANK() OVER(..)
+- [x] RAND()
+- [x] RANK() OVER(..)
+- [x] SUM(_) OVER(..)
+- [x] EXP(_)
+- [x] MAX(_)
+- [x] GENERATE_UUID()
+- [x] LEAST(*)
+- [x] APPROX_QUANTILES(_,_)
+- [x] LAG(_) OVER(..)
+- [x] FIRST_VALUE(_) OVER(..)
+
+Arrays:
+
+- [ ] ARRAY_TO_STRING(_,_)
+- [ ] ARRAY_AGG(_)
 - [ ] ARRAY_LENGTH(_)
-- [ ] SUM(_) OVER(..)
-- [ ] DATETIME_SUB(_,_)
-- [ ] DATE_DIFF(_,_,_) (special)
+
+Special date functions:
+
 - [ ] CURRENT_DATETIME()
-- [ ] DATE_SUB(_,_)
-- [ ] EXP(_)
-- [x] MAX(_)
-- [ ] GENERATE_UUID()
 - [ ] DATE(_)
-- [ ] LEAST(_,_)
-- [ ] APPROX_QUANTILES(_,_)
-- [ ] GENERATE_DATE_ARRAY(_,_,_)
 - [ ] DATE_ADD(_,_)
-- [ ] LAG(_) OVER(..)
+- [ ] DATE_DIFF(_,_,_) (special)
+- [ ] DATE_SUB(_,_)
+- [ ] DATE_TRUNC(_,_) (special)
+- [ ] DATETIME(_)
 - [ ] DATETIME_DIFF(_,_,_) (special)
+- [ ] DATETIME_SUB(_,_)
 - [ ] DATETIME_TRUNC(_,_) (special)
-- [ ] FIRST_VALUE(_) OVER(..)
-- [ ] DATETIME(_)
-- [ ] LEAST(_)
+- [ ] FORMAT_DATETIME(_,_)
+- [ ] GENERATE_DATE_ARRAY(_,_,_)
diff --git a/tests/sql/functions/aggregate/any_value.sql b/tests/sql/functions/aggregate/any_value.sql
new file mode 100644
index 0000000..475d02a
--- /dev/null
+++ b/tests/sql/functions/aggregate/any_value.sql
@@ -0,0 +1,13 @@
+-- pending: sqlite3 ANY_VALUES is not available.
+
+CREATE TEMP TABLE vals (i INT64);
+INSERT INTO vals VALUES (1), (1);
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT ANY_VALUE(i) AS any_value FROM vals;
+
+CREATE OR REPLACE TABLE __expected1 (
+    any_value INT64,
+);
+INSERT INTO __expected1 VALUES
+  (1);
\ No newline at end of file
diff --git a/tests/sql/functions/aggregate/approx_quantiles.sql b/tests/sql/functions/aggregate/approx_quantiles.sql
new file mode 100644
index 0000000..377abea
--- /dev/null
+++ b/tests/sql/functions/aggregate/approx_quantiles.sql
@@ -0,0 +1,15 @@
+-- pending: snowflake Use APPROX_PERCENTILE instead of APPROX_QUANTILES (complicated)
+-- pending: sqlite3 No APPROX_QUANTILES function
+
+CREATE TEMP TABLE quantile_data (x INT64);
+INSERT INTO quantile_data VALUES (1), (2), (3), (4), (5);
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT APPROX_QUANTILES(x, 2) AS approx_quantiles
+FROM quantile_data;
+
+CREATE OR REPLACE TABLE __expected1 (
+    approx_quantiles ARRAY<INT64>,
+);
+INSERT INTO __expected1 VALUES
+  ([1, 3, 5]);
diff --git a/tests/sql/functions/aggregate/countif.sql b/tests/sql/functions/aggregate/countif.sql
new file mode 100644
index 0000000..bbd5485
--- /dev/null
+++ b/tests/sql/functions/aggregate/countif.sql
@@ -0,0 +1,14 @@
+-- pending: snowflake COUNTIF can be rewritten portably by transpiler
+-- pending: sqlite3 COUNTIF Can be rewritten portably by transpiler
+
+CREATE TEMP TABLE vals (i INT64);
+INSERT INTO vals VALUES (1), (2), (2), (3), (NULL);
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT COUNTIF(i = 2) AS is2 FROM vals;
+
+CREATE OR REPLACE TABLE __expected1 (
+    is2 INT64,
+);
+INSERT INTO __expected1 VALUES
+  (2);
diff --git a/tests/sql/functions/simple/exp.sql b/tests/sql/functions/simple/exp.sql
new file mode 100644
index 0000000..c8281bd
--- /dev/null
+++ b/tests/sql/functions/simple/exp.sql
@@ -0,0 +1,11 @@
+-- pending: sqlite3 EXP is not available
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT
+    EXP(0.0) AS exp_zero;
+
+CREATE OR REPLACE TABLE __expected1 (
+    exp_zero FLOAT64,
+);
+INSERT INTO __expected1 VALUES
+  (1.0);
diff --git a/tests/sql/functions/simple/generate_uuid.sql b/tests/sql/functions/simple/generate_uuid.sql
new file mode 100644
index 0000000..3dce9fd
--- /dev/null
+++ b/tests/sql/functions/simple/generate_uuid.sql
@@ -0,0 +1,11 @@
+-- pending: sqlite3 Needs external function.
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT
+    LENGTH(generate_uuid()) AS uuid_length;
+
+CREATE OR REPLACE TABLE __expected1 (
+    uuid_length INT64,
+);
+INSERT INTO __expected1 VALUES
+  (36);
diff --git a/tests/sql/functions/simple/greatest_least.sql b/tests/sql/functions/simple/greatest_least.sql
new file mode 100644
index 0000000..eb3b860
--- /dev/null
+++ b/tests/sql/functions/simple/greatest_least.sql
@@ -0,0 +1,19 @@
+-- pending: sqlite3 GREATEST, LEAST are not available
+--
+-- GREATEST, LEAST
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT
+    GREATEST(1, 2, 3) AS greatest,
+    GREATEST(1, NULL, 3) AS greatest_null,
+    LEAST(1, 2, 3) AS least,
+    LEAST(1, NULL, 3) AS least_null;
+
+CREATE OR REPLACE TABLE __expected1 (
+    greatest INT64,
+    greatest_null INT64,
+    least INT64,
+    least_null INT64,
+);
+INSERT INTO __expected1 VALUES
+  (3, NULL, 1, NULL);
diff --git a/tests/sql/functions/simple/rand.sql b/tests/sql/functions/simple/rand.sql
new file mode 100644
index 0000000..0737441
--- /dev/null
+++ b/tests/sql/functions/simple/rand.sql
@@ -0,0 +1,11 @@
+-- pending: sqlite3 BigQuery RAND returns [0.0, 1.0), SQLite3 RANDOM() returns int
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT
+    RAND() BETWEEN 0.0 AND 1.0 AS rand_in_range;
+
+CREATE OR REPLACE TABLE __expected1 (
+    rand_in_range BOOL,
+);
+INSERT INTO __expected1 VALUES
+  (TRUE);
diff --git a/tests/sql/functions/windows/basic_windows.sql b/tests/sql/functions/windows/basic_windows.sql
index 19aaa9e..fda01cb 100644
--- a/tests/sql/functions/windows/basic_windows.sql
+++ b/tests/sql/functions/windows/basic_windows.sql
@@ -25,6 +25,7 @@ SELECT
     category,
     price,
     RANK() OVER (PARTITION BY category ORDER BY price) AS price_rank,
+    ROW_NUMBER() OVER (PARTITION BY category ORDER BY price) AS price_row_number,
     SUM(price) OVER (PARTITION BY category ORDER BY price ROWS UNBOUNDED PRECEDING) AS cummulative_price,
     SUM(price) OVER (PARTITION BY category ORDER BY price ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS cummulative_price2,
 FROM groceries;
@@ -34,14 +35,15 @@ CREATE OR REPLACE TABLE __expected1 (
     category STRING,
     price FLOAT64,
     price_rank INT64,
+    price_row_number INT64,
     cummulative_price FLOAT64,
     cummulative_price2 FLOAT64,
 );
 INSERT INTO __expected1 VALUES
-  ('apple', 'fruit', 1.0, 1, 1.0, 1.0),
-  ('banana', 'fruit', 1.5, 2, 2.5, 2.5),
-  ('carrot', 'vegetable', 0.75, 1, 0.75, 0.75),
-  ('eggplant', 'vegetable', 1.25, 2, 2.0, 2.0),
-  ('flour', 'baking', 0.25, 1, 0.25, 0.25),
-  ('sugar', 'baking', 0.5, 2, 0.75, 0.75),
-  ('salt', 'baking', 0.75, 3, 1.5, 1.5);
+  ('apple', 'fruit', 1.0, 1, 1, 1.0, 1.0),
+  ('banana', 'fruit', 1.5, 2, 2, 2.5, 2.5),
+  ('carrot', 'vegetable', 0.75, 1, 1, 0.75, 0.75),
+  ('eggplant', 'vegetable', 1.25, 2, 2, 2.0, 2.0),
+  ('flour', 'baking', 0.25, 1, 1, 0.25, 0.25),
+  ('sugar', 'baking', 0.5, 2, 2, 0.75, 0.75),
+  ('salt', 'baking', 0.75, 3, 3, 1.5, 1.5);
diff --git a/tests/sql/functions/windows/first_last_value.sql b/tests/sql/functions/windows/first_last_value.sql
new file mode 100644
index 0000000..5afffe1
--- /dev/null
+++ b/tests/sql/functions/windows/first_last_value.sql
@@ -0,0 +1,39 @@
+-- pending: sqlite3 FIRST_VALUE, LAST_VALUE seem to require frames to work?
+
+-- FIRST_VALUE, LAST_VALUE
+
+-- A fixture table for testing window functions.
+CREATE TEMP TABLE groceries (
+  item STRING,
+  category STRING,
+  price FLOAT64,
+);
+INSERT INTO groceries VALUES
+    ('apple', 'fruit', 1.00),
+    ('banana', 'fruit', 1.50),
+    ('carrot', 'vegetable', 0.75),
+    ('eggplant', 'vegetable', 1.25),
+    ('sugar', 'baking', 0.50),
+    ('flour', 'baking', 0.25),
+    ('salt', 'baking', 0.75);
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT
+    item,
+    FIRST_VALUE(item) OVER (PARTITION BY category ORDER BY price) AS cheapest_alternative,
+    LAST_VALUE(item) OVER (PARTITION BY category ORDER BY price) AS most_expensive_alternative,
+FROM groceries;
+
+CREATE OR REPLACE TABLE __expected1 (
+    item STRING,
+    cheapest_alternative STRING,
+    most_expensive_alternative STRING,
+);
+INSERT INTO __expected1 VALUES
+  ('apple', 'apple', 'banana'),
+  ('banana', 'apple', 'banana'),
+  ('carrot', 'carrot', 'eggplant'),
+  ('eggplant', 'carrot', 'eggplant'),
+  ('flour', 'flour', 'salt'),
+  ('sugar', 'flour', 'salt'),
+  ('salt', 'flour', 'salt');
diff --git a/tests/sql/functions/windows/lag.sql b/tests/sql/functions/windows/lag.sql
new file mode 100644
index 0000000..1d4b272
--- /dev/null
+++ b/tests/sql/functions/windows/lag.sql
@@ -0,0 +1,19 @@
+-- LAG
+
+CREATE TEMP TABLE fruits (idx INT64, fruit_name STRING);
+INSERT INTO fruits VALUES (1, 'apple'), (2, 'banana'), (3, 'cherry');
+
+CREATE OR REPLACE TABLE __result1 AS
+SELECT
+    fruit_name,
+    LAG(fruit_name) OVER (ORDER BY idx) AS previous_fruit
+FROM fruits;
+
+CREATE OR REPLACE TABLE __expected1 (
+    fruit_name STRING,
+    previous_fruit STRING,
+);
+INSERT INTO __expected1 VALUES
+  ('apple', NULL),
+  ('banana', 'apple'),
+  ('cherry', 'banana');