type RestrictedSQLExecutor interface {
	// ExecRestrictedSQL run sql statement in ctx with some restriction.
	ExecRestrictedSQL(sql string) ([]chunk.Row, []*ast.ResultField, error)
}

sql  = fmt.Sprintf('select xxx from ..%s ', varFromOutside)
stmt, err = ExecRestrictedSQL(sql) 
...

	// ExecRestrictedSQLWithContext run sql statement in ctx with some restriction.
	ExecRestrictedSQLWithContext(ctx context.Context, sql string, opts ...OptionFuncAlias) ([]chunk.Row, []*ast.ResultField, error)
	// ExecRestrictedSQLWithSnapshot run sql statement in ctx with some restriction and with snapshot.
	// If current session sets the snapshot timestamp, then execute with this snapshot timestamp.
	// Otherwise, execute with the current transaction start timestamp if the transaction is valid.
	ExecRestrictedSQLWithSnapshot(sql string) ([]chunk.Row, []*ast.ResultField, error)

type RestrictedSQLExecutor interface {
	ParseWithParams(ctx context.Context, sql string, args ...interface{}) (ast.StmtNode, error)
	ExecRestrictedStmt(ctx context.Context, stmt ast.StmtNode, opts ...OptionFuncAlias) ([]chunk.Row, []*ast.ResultField, error)
}

stmt  = exec.ParseWithParams('select xxx from ..%? ', varFromOutside)
res, err = ExecRestrictedSQL(stmt) 
...