stage1

Documentation

Overview

Package stage1. check and init, we cannot support all features, we will try to remove these unsupported features. For features that cannot be removed, we will throw errors.

1. remove aggregate functions(and GROUP BY).

2. remove window functions.

3. remove LEFT|RIGHT JOIN

4. remove Limit

5. remove uncertain functions

Note that:

(1) we only support SELECT statement.

(2) make sure your sql has no side-effects, such as assign operations, SELECT into.

(3) The transformed sql may fail to execute.

How to use: see Init, InitAndExec

Index

• type InitResult
  • func Init(sql string) *InitResult
  • func InitAndExec(sql string, conn *connector.Connector) *InitResult
• type InitVisitor
  • func (v *InitVisitor) Enter(in ast.Node) (ast.Node, bool)
  • func (v *InitVisitor) Leave(in ast.Node) (ast.Node, bool)

Types

type InitResult

type InitResult struct {
	InitSql    string
	Err        error
	ExecResult *connector.Result
}

func Init

func Init(sql string) *InitResult

Init: for the input sql, remove aggregate functions(and GROUP BY), window functions, LEFT|RIGHT JOIN, LIMIT, uncertain functions.

Note that:

(1) we only support SELECT statement.

(2) make sure your sql has no side-effects, such as assign operations, SELECT into.

(3) The transformed sql may fail to execute.

func InitAndExec

func InitAndExec(sql string, conn *connector.Connector) *InitResult

InitAndExec: Init + exec

type InitVisitor

type InitVisitor struct {
}

func (*InitVisitor) Enter

func (v *InitVisitor) Enter(in ast.Node) (ast.Node, bool)

func (*InitVisitor) Leave

func (v *InitVisitor) Leave(in ast.Node) (ast.Node, bool)