Merge pull request #3217 from dolthub/elian/dbvr-tests

Add `CREATE DATABASE` fall back on `CREATE SCHEMA` to mirror MySQL

Author: elianddb

enginetest/queries/script_queries.go

@@ -13519,6 +13519,52 @@ var BrokenScriptTests = []ScriptTest{
 }
 
 var CreateDatabaseScripts = []ScriptTest{
+	{
+		// https://github.com/dolthub/dolt/pull/9830
+		Name: "CREATE SCHEMA without database selection falls back to CREATE DATABASE",
+		SetUpScript: []string{
+			"CREATE DATABASE tmp",
+			"USE tmp",
+		},
+		Dialect: "mysql",
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: "DROP DATABASE tmp",
+			},
+			{
+				Query:    "CREATE SCHEMA NewDatabase",
+				Expected: []sql.Row{{types.OkResult{RowsAffected: 1}}},
+			},
+			{
+				Query:    "SHOW DATABASES",
+				Expected: []sql.Row{{"NewDatabase"}, {"information_schema"}, {"mydb"}, {"mysql"}},
+			},
+			{
+				Query:    "USE NewDatabase",
+				Expected: []sql.Row{},
+			},
+			{
+				Query:    "SELECT DATABASE()",
+				Expected: []sql.Row{{"NewDatabase"}},
+			},
+			{
+				Query:    "CREATE TABLE test_table (id INT PRIMARY KEY)",
+				Expected: []sql.Row{{types.OkResult{RowsAffected: 0}}},
+			},
+			{
+				Query:    "SHOW TABLES",
+				Expected: []sql.Row{{"test_table"}},
+			},
+			{
+				Query:    "USE mydb",
+				Expected: []sql.Row{},
+			},
+			{
+				Query:    "DROP DATABASE NewDatabase",
+				Expected: []sql.Row{{types.OkResult{RowsAffected: 1}}},
+			},
+		},
+	},
 	{
 		Name: "CREATE DATABASE and create table",
 		Assertions: []ScriptTestAssertion{

sql/rowexec/ddl.go

@@ -405,8 +405,18 @@ func (b *BaseBuilder) buildCreateDB(ctx *sql.Context, n *plan.CreateDB, row sql.
 
 func (b *BaseBuilder) buildCreateSchema(ctx *sql.Context, n *plan.CreateSchema, row sql.Row) (sql.RowIter, error) {
 	database := ctx.GetCurrentDatabase()
+
+	// If no database is selected, first try to fall back to CREATE DATABASE
+	// since CREATE SCHEMA is a synonym for CREATE DATABASE in MySQL
+	// https://dev.mysql.com/doc/refman/8.4/en/create-database.html
+	// TODO: For PostgreSQL, return an error if no database is selected.
 	if database == "" {
-		return nil, sql.ErrNoDatabaseSelected.New()
+		return b.buildCreateDB(ctx, &plan.CreateDB{
+			Catalog:     n.Catalog,
+			DbName:      n.DbName,
+			IfNotExists: n.IfNotExists,
+			Collation:   n.Collation,
+		}, row)
 	}
 
 	db, err := n.Catalog.Database(ctx, database)