diff --git a/src/test/kotlin/kestrel/CompoundQueryTest.kt b/src/test/kotlin/kestrel/CompoundQueryTest.kt
new file mode 100644
index 0000000..e856f11
--- /dev/null
+++ b/src/test/kotlin/kestrel/CompoundQueryTest.kt
@@ -0,0 +1,162 @@
+package kestrel
+
+import kestrel.catalog.Catalog
+import kestrel.engine.ExplainResult
+import kestrel.engine.Executor
+import kestrel.engine.SelectResult
+import kestrel.engine.StatementResult
+import kestrel.sql.lexer.Lexer
+import kestrel.sql.parser.Parser
+import kestrel.storage.Value
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import kotlin.test.assertTrue
+
+class CompoundQueryTest {
+    private val catalog = Catalog()
+    private val executor = Executor(catalog)
+
+    private fun run(sql: String): List<StatementResult> =
+        Parser(Lexer(sql).tokenize()).parseProgram().map { executor.execute(it) }
+
+    private fun select(sql: String): SelectResult = run(sql).single() as SelectResult
+
+    private fun int(value: Long) = Value.IntegerValue(value)
+    private fun text(value: String) = Value.TextValue(value)
+
+    private fun seed() {
+        run("CREATE TABLE dual (x INTEGER)")
+        run("INSERT INTO dual VALUES (1)")
+        run("CREATE TABLE t1 (id INTEGER PRIMARY KEY, name TEXT NOT NULL)")
+        run("CREATE TABLE t2 (id INTEGER PRIMARY KEY, name TEXT NOT NULL)")
+        run("INSERT INTO t1 VALUES (1, 'ada'), (2, 'linus')")
+        run("INSERT INTO t2 VALUES (2, 'linus'), (3, 'grace')")
+    }
+
+    @Test
+    fun unionRemovesDuplicateRows() {
+        seed()
+        val result = select("SELECT name FROM t1 UNION SELECT name FROM t2 ORDER BY name")
+        assertEquals(listOf(listOf(text("ada")), listOf(text("grace")), listOf(text("linus"))), result.rows)
+    }
+
+    @Test
+    fun unionAllKeepsDuplicateRows() {
+        seed()
+        val result = select("SELECT name FROM t1 UNION ALL SELECT name FROM t2 ORDER BY name")
+        assertEquals(
+            listOf(listOf(text("ada")), listOf(text("grace")), listOf(text("linus")), listOf(text("linus"))),
+            result.rows
+        )
+    }
+
+    @Test
+    fun intersectReturnsRowsPresentInBothQueries() {
+        seed()
+        val result = select("SELECT name FROM t1 INTERSECT SELECT name FROM t2")
+        assertEquals(listOf(listOf(text("linus"))), result.rows)
+    }
+
+    @Test
+    fun exceptReturnsRowsOnlyInTheLeftQuery() {
+        seed()
+        val result = select("SELECT name FROM t1 EXCEPT SELECT name FROM t2")
+        assertEquals(listOf(listOf(text("ada"))), result.rows)
+    }
+
+    @Test
+    fun intersectAllKeepsDuplicatesUpToTheMinimumCountInEitherSide() {
+        run("CREATE TABLE bag_a (v INTEGER)")
+        run("CREATE TABLE bag_b (v INTEGER)")
+        run("INSERT INTO bag_a VALUES (1), (1), (1), (2)")
+        run("INSERT INTO bag_b VALUES (1), (1), (2), (2), (3)")
+        val result = select("SELECT v FROM bag_a INTERSECT ALL SELECT v FROM bag_b ORDER BY v")
+        assertEquals(listOf(listOf(int(1)), listOf(int(1)), listOf(int(2))), result.rows)
+    }
+
+    @Test
+    fun exceptAllKeepsLeftDuplicatesNotConsumedByTheRightSide() {
+        run("CREATE TABLE bag_a (v INTEGER)")
+        run("CREATE TABLE bag_b (v INTEGER)")
+        run("INSERT INTO bag_a VALUES (1), (1), (1), (2)")
+        run("INSERT INTO bag_b VALUES (1), (1), (2), (2), (3)")
+        val result = select("SELECT v FROM bag_a EXCEPT ALL SELECT v FROM bag_b ORDER BY v")
+        assertEquals(listOf(listOf(int(1))), result.rows)
+    }
+
+    @Test
+    fun mismatchedColumnCountsFail() {
+        seed()
+        assertFailsWith<KestrelException> {
+            select("SELECT id, name FROM t1 UNION SELECT id FROM t2")
+        }
+    }
+
+    @Test
+    fun compoundOperatorsChainLeftAssociatively() {
+        seed()
+        run("CREATE TABLE t3 (id INTEGER PRIMARY KEY, name TEXT NOT NULL)")
+        run("INSERT INTO t3 VALUES (2, 'linus')")
+        val result = select("SELECT name FROM t1 UNION ALL SELECT name FROM t2 INTERSECT SELECT name FROM t3 ORDER BY name")
+        assertEquals(listOf(listOf(text("linus"))), result.rows)
+    }
+
+    @Test
+    fun orderByAndLimitApplyToTheWholeCompoundResult() {
+        seed()
+        val result = select("SELECT name FROM t1 UNION ALL SELECT name FROM t2 ORDER BY name DESC LIMIT 2")
+        assertEquals(listOf(listOf(text("linus")), listOf(text("linus"))), result.rows)
+    }
+
+    @Test
+    fun offsetSkipsRowsOfTheWholeCompoundResultBeforeLimitApplies() {
+        seed()
+        val result = select("SELECT name FROM t1 UNION ALL SELECT name FROM t2 ORDER BY name DESC LIMIT 2 OFFSET 1")
+        assertEquals(listOf(listOf(text("linus")), listOf(text("grace"))), result.rows)
+    }
+
+    @Test
+    fun compoundQueryWorksAsDerivedTableInFrom() {
+        seed()
+        val result = select("SELECT count(*) FROM (SELECT name FROM t1 UNION SELECT name FROM t2) AS u")
+        assertEquals(listOf(listOf(int(3))), result.rows)
+    }
+
+    @Test
+    fun compoundQueryWorksAsViewBody() {
+        seed()
+        run("CREATE VIEW combined AS SELECT name FROM t1 UNION SELECT name FROM t2")
+        val result = select("SELECT name FROM combined ORDER BY name")
+        assertEquals(listOf(listOf(text("ada")), listOf(text("grace")), listOf(text("linus"))), result.rows)
+        run("INSERT INTO t1 VALUES (4, 'margaret')")
+        val refreshed = select("SELECT name FROM combined ORDER BY name")
+        assertEquals(4, refreshed.rows.size)
+    }
+
+    @Test
+    fun explainDescribesCompoundQuery() {
+        seed()
+        val plan = (run("EXPLAIN SELECT name FROM t1 UNION SELECT name FROM t2").single() as ExplainResult).plan
+        assertTrue(plan.isNotEmpty())
+        assertTrue(plan.any { it.contains("Union") })
+    }
+
+    @Test
+    fun withClauseMakesACteAvailableInFrom() {
+        seed()
+        run("WITH recent AS (SELECT id, name FROM t1) SELECT name FROM recent WHERE id = 1")
+        val result = select("WITH recent AS (SELECT id, name FROM t1) SELECT name FROM recent WHERE id = 1")
+        assertEquals(listOf(listOf(text("ada"))), result.rows)
+    }
+
+    @Test
+    fun laterCteCanReferenceAnEarlierCteInTheSameWithClause() {
+        seed()
+        val result = select(
+            "WITH first_cte AS (SELECT id, name FROM t1), second_cte AS (SELECT name FROM first_cte WHERE id = 2) " +
+                "SELECT name FROM second_cte"
+        )
+        assertEquals(listOf(listOf(text("linus"))), result.rows)
+    }
+