From d2fbdb68e6acb32d7aecd8cc17d9952015f1a19f Mon Sep 17 00:00:00 2001
From: go-jet <zer0.sub@protonmail.com>
Date: Sat, 14 Dec 2019 19:11:35 +0100
Subject: [PATCH] Add support for conditional constructed projection list.

---
 mysql/types.go                |  3 +++
 postgres/types.go             |  3 +++
 tests/mysql/select_test.go    | 33 +++++++++++++++++++++++++++++++++
 tests/postgres/select_test.go | 33 +++++++++++++++++++++++++++++++++
 4 files changed, 72 insertions(+)

diff --git a/mysql/types.go b/mysql/types.go
index 2902e72..4ef84b4 100644
--- a/mysql/types.go
+++ b/mysql/types.go
@@ -7,3 +7,6 @@ type Statement = jet.Statement
 
 // Projection is interface for all projection types. Types that can be part of, for instance SELECT clause.
 type Projection = jet.Projection
+
+// ProjectionList can be used to create conditional constructed projection list.
+type ProjectionList = jet.ProjectionList
diff --git a/postgres/types.go b/postgres/types.go
index 215cceb..58a8ae9 100644
--- a/postgres/types.go
+++ b/postgres/types.go
@@ -7,3 +7,6 @@ type Statement = jet.Statement
 
 // Projection is interface for all projection types. Types that can be part of, for instance SELECT clause.
 type Projection = jet.Projection
+
+// ProjectionList can be used to create conditional constructed projection list.
+type ProjectionList = jet.ProjectionList
diff --git a/tests/mysql/select_test.go b/tests/mysql/select_test.go
index 952eb63..ed75bad 100644
--- a/tests/mysql/select_test.go
+++ b/tests/mysql/select_test.go
@@ -708,3 +708,36 @@ func TestJoinViewWithTable(t *testing.T) {
 	assert.Equal(t, len(dest[0].Rentals), 32)
 	assert.Equal(t, len(dest[1].Rentals), 27)
 }
+
+func TestConditionalProjectionList(t *testing.T) {
+	projectionList := ProjectionList{}
+
+	columnsToSelect := []string{"customer_id", "create_date"}
+
+	for _, columnName := range columnsToSelect {
+		switch columnName {
+		case Customer.CustomerID.Name():
+			projectionList = append(projectionList, Customer.CustomerID)
+		case Customer.Email.Name():
+			projectionList = append(projectionList, Customer.Email)
+		case Customer.CreateDate.Name():
+			projectionList = append(projectionList, Customer.CreateDate)
+		}
+	}
+
+	stmt := SELECT(projectionList).
+		FROM(Customer).
+		LIMIT(3)
+
+	testutils.AssertDebugStatementSql(t, stmt, `
+SELECT customer.customer_id AS "customer.customer_id",
+     customer.create_date AS "customer.create_date"
+FROM dvds.customer
+LIMIT 3;
+`)
+	var dest []model.Customer
+	err := stmt.Query(db, &dest)
+	assert.NilError(t, err)
+
+	assert.Equal(t, len(dest), 3)
+}
diff --git a/tests/postgres/select_test.go b/tests/postgres/select_test.go
index 2ac6c36..35ba373 100644
--- a/tests/postgres/select_test.go
+++ b/tests/postgres/select_test.go
@@ -1791,3 +1791,36 @@ func TestJoinViewWithTable(t *testing.T) {
 	assert.Equal(t, len(dest[0].Rentals), 32)
 	assert.Equal(t, len(dest[1].Rentals), 27)
 }
+
+func TestConditionalProjectionList(t *testing.T) {
+	projectionList := ProjectionList{}
+
+	columnsToSelect := []string{"customer_id", "create_date"}
+
+	for _, columnName := range columnsToSelect {
+		switch columnName {
+		case Customer.CustomerID.Name():
+			projectionList = append(projectionList, Customer.CustomerID)
+		case Customer.Email.Name():
+			projectionList = append(projectionList, Customer.Email)
+		case Customer.CreateDate.Name():
+			projectionList = append(projectionList, Customer.CreateDate)
+		}
+	}
+
+	stmt := SELECT(projectionList).
+		FROM(Customer).
+		LIMIT(3)
+
+	testutils.AssertDebugStatementSql(t, stmt, `
+SELECT customer.customer_id AS "customer.customer_id",
+     customer.create_date AS "customer.create_date"
+FROM dvds.customer
+LIMIT 3;
+`)
+	var dest []model.Customer
+	err := stmt.Query(db, &dest)
+	assert.NilError(t, err)
+
+	assert.Equal(t, len(dest), 3)
+}