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Mar 11, 2025
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Add implementation of LET clause and LetTests #1745

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59e4916
Add implementation of LET clause and LetTests
Mar 6, 2025
156d2a5
Add one more test for testing multiple LET clauses
Mar 11, 2025
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259 changes: 259 additions & 0 deletions partiql-eval/src/test/kotlin/org/partiql/eval/internal/LetTests.kt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,259 @@
package org.partiql.eval.internal

import org.junit.jupiter.api.Disabled
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.parallel.Execution
import org.junit.jupiter.api.parallel.ExecutionMode
import org.junit.jupiter.params.ParameterizedTest
import org.junit.jupiter.params.provider.MethodSource
import org.partiql.spi.value.Datum
import org.partiql.spi.value.Field

/**
* This test file exercises the `LET` clause in PartiQL.
*/
class LetTests {

@ParameterizedTest
@MethodSource("successTestCases")
@Execution(ExecutionMode.CONCURRENT)
fun successTests(tc: SuccessTestCase) = tc.run()

@ParameterizedTest
@MethodSource("failureTestCases")
@Execution(ExecutionMode.CONCURRENT)
fun failureTests(tc: FailureTestCase) = tc.run()

companion object {

@JvmStatic
fun successTestCases() = listOf(
SuccessTestCase(
name = "Basic LET usage 1",
input = """
SELECT t.a, c
FROM <<{ 'a': 1 , 'b': 2}>> AS t
LET t.a*5 AS c
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("a", Datum.integer(1)),
Field.of("c", Datum.integer(5))
)
)
),

SuccessTestCase(
name = "Basic LET usage 2",
input = """
SELECT t.x, t.y, t.z * 2 AS double_z
FROM (
SELECT A AS x, B AS y, new_val AS z
FROM <<{ 'A': 1, 'B': 2, 'C': 3}>>
LET B + C AS new_val
) AS t;
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("x", Datum.integer(1)),
Field.of("y", Datum.integer(2)),
Field.of("double_z", Datum.integer(10))
)
)
),

SuccessTestCase(
name = "LET with JOIN operation",
input = """
SELECT t.customer_name, t.order_total
FROM (
SELECT
c.name AS customer_name,
total AS order_total
FROM <<
{ 'id': 1, 'name': 'Alice' },
{ 'id': 2, 'name': 'Bob' }
>> AS c
JOIN <<
{ 'customer_id': 1, 'amount': 100 },
{ 'customer_id': 1, 'amount': 200 },
{ 'customer_id': 2, 'amount': 150 }
>> AS o
ON c.id = o.customer_id
LET o.amount * c.id AS total
) AS t;
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("customer_name", Datum.string("Alice")),
Field.of("order_total", Datum.integer(100))
),
Datum.struct(
Field.of("customer_name", Datum.string("Alice")),
Field.of("order_total", Datum.integer(200))
),
Datum.struct(
Field.of("customer_name", Datum.string("Bob")),
Field.of("order_total", Datum.integer(300))
)
)
),

SuccessTestCase(
name = "LET with multiple items in data",
input = """
SELECT t.x, t.y, t.z AS total
FROM (
SELECT A AS x, B AS y, sum_val AS z
FROM <<
{ 'A': 1, 'B': 2, 'C': 3 },
{ 'A': 10, 'B': 20, 'C': 30 }
>>
LET B + C AS sum_val
) AS t;
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("x", Datum.integer(1)),
Field.of("y", Datum.integer(2)),
Field.of("total", Datum.integer(5))
),
Datum.struct(
Field.of("x", Datum.integer(10)),
Field.of("y", Datum.integer(20)),
Field.of("total", Datum.integer(50))
)
)
),
SuccessTestCase(
name = "LET referencing prior expressions",
input = """
SELECT t.x, t.sum_val, t.double_sum
FROM (
SELECT
A AS x,
sum_val,
sum_val * 2 AS double_sum
FROM <<
{ 'A': 3, 'B': 5 },
{ 'A': 10, 'B': 2 }
>>
LET A + B AS sum_val
) AS t;
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("x", Datum.integer(3)),
Field.of("sum_val", Datum.integer(8)),
Field.of("double_sum", Datum.integer(16))
),
Datum.struct(
Field.of("x", Datum.integer(10)),
Field.of("sum_val", Datum.integer(12)),
Field.of("double_sum", Datum.integer(24))
)
)
),
SuccessTestCase(
name = "LET with multiple LET clauses 1",
input = """
SELECT t.a, b, c
FROM << { 'a': 1 }>> AS t
LET t.a + 2 AS b, t.a * 3 AS c
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("a", Datum.integer(1)),
Field.of("b", Datum.integer(3)),
Field.of("c", Datum.integer(3))
)
)
),
SuccessTestCase(
name = "LET with multiple LET clauses 2",
input = """
SELECT a, b, c, d, e
FROM << { 'a': 1 , 'b':2}>> AS t
LET t.a + 5 AS c, t.b+ 10 AS d, t.a + 15 AS e
""".trimIndent(),
expected = Datum.bagVararg(
Datum.struct(
Field.of("a", Datum.integer(1)),
Field.of("b", Datum.integer(2)),
Field.of("c", Datum.integer(6)),
Field.of("d", Datum.integer(12)),
Field.of("e", Datum.integer(16))
)
)
)
)

@JvmStatic
fun failureTestCases() = listOf(
FailureTestCase(
name = "LET referencing undefined variable",
input = """
SELECT t.x
FROM (
SELECT A AS x
FROM << { 'A': 1, 'B': 2 } >>
LET nonexistent + B AS new_val
) AS t;
""".trimIndent()
),
FailureTestCase(
name = "LET clause with ambiguous reference",
input = """
SELECT t.z
FROM (
SELECT new_val AS z
FROM << { 'A': 1, 'B': 2 } >>
-- 'new_val' references itself in LET, which is not allowed
LET new_val + B AS new_val
) AS t;
""".trimIndent()
),
FailureTestCase(
name = "Outside clauses referencing subquery's LET bindings",
input = """
SELECT t.x, t.y, new_val
FROM (
SELECT A AS x, B AS y
FROM <<{ 'A': 1, 'B': 2, 'C': 3}>>
LET B + C AS new_val
) AS t;
""".trimIndent()
),
FailureTestCase(
name = "LET with invalid JOIN reference",
input = """
SELECT t.customer_name, t.calculated_total
FROM (
SELECT
c.name AS customer_name,
total AS calculated_total
FROM <<
{ 'id': 1, 'name': 'Alice' },
{ 'id': 2, 'name': 'Bob' }
>> AS c
LEFT JOIN <<
{ 'customer_id': 1, 'amount': 100 },
{ 'customer_id': 2, 'amount': 150 }
>> AS o
ON c.id = o.customer_id
-- This should fail because we're trying to reference 'missing_field'
-- which doesn't exist in either joined table
LET missing_field + o.amount AS total
) AS t;
""".trimIndent(),
)
)
}

// Example of a test that might need special handling or a skip
@Test
@Disabled("Demonstration of a scenario needing further investigation.")
fun disabledTestExample() {
// Implementation left blank or used for demonstration
}
}
33 changes: 33 additions & 0 deletions partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/RelConverter.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,8 @@ import org.partiql.ast.GroupBy
import org.partiql.ast.GroupByStrategy
import org.partiql.ast.Identifier
import org.partiql.ast.JoinType
import org.partiql.ast.Let
import org.partiql.ast.Let.Binding
import org.partiql.ast.Literal.intNum
import org.partiql.ast.Nulls
import org.partiql.ast.Order
Expand Down Expand Up @@ -192,6 +194,7 @@ internal object RelConverter {
rel = convertOffset(rel, offset)
rel = convertLimit(rel, limit)
rel = convertExclude(rel, sel.exclude)
rel = convertLet(rel, sel.let)
// append SQL projection if present
rel = when (val projection = sel.select) {
is SelectValue -> {
Expand Down Expand Up @@ -383,6 +386,13 @@ internal object RelConverter {
return binding to rex
}

private fun convertLetBinding(binding: Binding): Pair<Rel.Binding, Rex> {
val name = binding.asAlias.text
val rex = RexConverter.apply(binding.expr, env)
val newBinding = relBinding(name, rex.type)
return newBinding to rex
}

/**
* Append [Rel.Op.Filter] only if a WHERE condition exists
*/
Expand Down Expand Up @@ -582,6 +592,29 @@ internal object RelConverter {
return rel(type, op)
}

/**
* Concatenate bindings in LET clause with existing env bindings from input
*/
private fun convertLet(input: Rel, let: Let?): Rel {
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will add tests in amendment

if (let == null) {
return input
}
val schema = input.type.schema.toMutableList()
val props = input.type.props
val projections = mutableListOf<Rex>()
repeat(input.type.schema.size) { index ->
projections.add(rex(ANY, rexOpVarLocal(0, index)))
}
let.bindings.forEach {
val (newBinding, projection) = convertLetBinding(it)
schema.add(newBinding)
projections.add(projection)
}
val type = relType(schema, props)
val op = relOpProject(input, projections)
return rel(type, op)
}

/**
* Append [Rel.Op.Offset] if there is an OFFSET
*/
Expand Down
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