fix(engine/mysql): Add support for MySQL ON DUPLICATE KEY UPDATE (#1286)

* fix(engine/mysql): Add support for MySQL ON DUPLICATE KEY UPDATE

* Remove unnecessary action

Author: timstudd

internal/endtoend/testdata/on_duplicate_key_update/mysql/db/db.go

@@ -0,0 +1,13 @@
+-- https://github.com/kyleconroy/sqlc/issues/921
+CREATE TABLE authors (
+  id   BIGINT  NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  name text    NOT NULL,
+  bio  text,
+  UNIQUE(name)
+);
+
+-- name: UpsertAuthor :exec
+INSERT INTO authors (name, bio)
+VALUES (?, ?)
+ON DUPLICATE KEY
+    UPDATE bio = ?;

internal/endtoend/testdata/on_duplicate_key_update/mysql/db/models.go

@@ -0,0 +1,11 @@
+{
+	"version":"1",
+	"packages":[
+		{
+			"path":"db",
+			"engine":"mysql",
+			"schema":"query.sql",
+			"queries":"query.sql"
+		}
+	]
+}

internal/endtoend/testdata/on_duplicate_key_update/mysql/db/query.sql.go

@@ -0,0 +1,12 @@
+-- https://github.com/kyleconroy/sqlc/issues/921
+CREATE TABLE authors (
+  id   BIGSERIAL PRIMARY KEY,
+  name text      NOT NULL UNIQUE,
+  bio  text
+);
+
+-- name: UpsertAuthor :exec
+INSERT INTO authors (name, bio)
+VALUES ($1, $2)
+ON CONFLICT (name) DO UPDATE
+SET bio = $2;

internal/endtoend/testdata/on_duplicate_key_update/mysql/query.sql

@@ -0,0 +1,11 @@
+{
+	"version":"1",
+	"packages":[
+		{
+			"path":"db",
+			"engine":"postgresql",
+			"schema":"query.sql",
+			"queries":"query.sql"
+		}
+	]
+}

internal/endtoend/testdata/on_duplicate_key_update/mysql/sqlc.json

@@ -407,6 +407,18 @@ func (c *cc) convertInsertStmt(n *pcast.InsertStmt) *ast.InsertStmt {
 			ValuesLists: c.convertLists(n.Lists),
 		}
 	}
+
+	if n.OnDuplicate != nil {
+		targetList := &ast.List{}
+		for _, a := range n.OnDuplicate {
+			targetList.Items = append(targetList.Items, c.convertAssignment(a))
+		}
+		insert.OnConflictClause = &ast.OnConflictClause{
+			TargetList: targetList,
+			Location:   n.OriginTextPosition(),
+		}
+	}
+
 	return insert
 }