func (r *Router) generateSelectSql(plan *Plan, stmt sqlparser.Statement) error {
sqls := make(map[string][]string)
node, ok := stmt.(*sqlparser.Select)
if ok == false {
return errors.ErrStmtConvert
}
if len(plan.RouteNodeIndexs) == 0 {
return errors.ErrNoRouteNode
}
if len(plan.RouteTableIndexs) == 0 {
buf := sqlparser.NewTrackedBuffer(nil)
stmt.Format(buf)
nodeName := r.Nodes[0]
sqls[nodeName] = []string{buf.String()}
} else {
tableCount := len(plan.RouteTableIndexs)
for i := 0; i < tableCount; i++ {
tableIndex := plan.RouteTableIndexs[i]
nodeIndex := plan.Rule.TableToNode[tableIndex]
nodeName := r.Nodes[nodeIndex]
selectSql := r.rewriteSelectSql(plan, node, tableIndex)
if _, ok := sqls[nodeName]; ok == false {
sqls[nodeName] = make([]string, 0, tableCount)
}
sqls[nodeName] = append(sqls[nodeName], selectSql)
}
}
plan.RewrittenSqls = sqls
return nil
}
func (r *Router) generateReplaceSql(plan *Plan, stmt sqlparser.Statement) error {
sqls := make(map[string][]string)
node, ok := stmt.(*sqlparser.Replace)
if ok == false {
return errors.ErrStmtConvert
}
if len(plan.RouteNodeIndexs) == 0 {
return errors.ErrNoRouteNode
}
if len(plan.RouteTableIndexs) == 0 {
buf := sqlparser.NewTrackedBuffer(nil)
stmt.Format(buf)
nodeName := r.Nodes[0]
sqls[nodeName] = []string{buf.String()}
} else {
tableCount := len(plan.RouteTableIndexs)
for i := 0; i < tableCount; i++ {
tableIndex := plan.RouteTableIndexs[i]
nodeIndex := plan.Rule.TableToNode[tableIndex]
nodeName := r.Nodes[nodeIndex]
buf := sqlparser.NewTrackedBuffer(nil)
buf.Fprintf("replace %vinto %v",
node.Comments,
node.Table,
)
fmt.Fprintf(buf, "_%04d", plan.RouteTableIndexs[i])
buf.Fprintf("%v %v",
node.Columns,
plan.Rows[tableIndex],
)
if _, ok := sqls[nodeName]; ok == false {
sqls[nodeName] = make([]string, 0, tableCount)
}
sqls[nodeName] = append(sqls[nodeName], buf.String())
}
}
plan.RewrittenSqls = sqls
return nil
}
//rewrite select sql
func (r *Router) rewriteSelectSql(plan *Plan, node *sqlparser.Select, tableIndex int) string {
buf := sqlparser.NewTrackedBuffer(nil)
buf.Fprintf("select %v%s%v",
node.Comments,
node.Distinct,
node.SelectExprs,
)
//insert the group columns in the first of select cloumns
if len(node.GroupBy) != 0 {
prefix := ","
for _, n := range node.GroupBy {
buf.Fprintf("%s%v", prefix, n)
}
}
buf.Fprintf(" from ")
switch v := (node.From[0]).(type) {
case *sqlparser.AliasedTableExpr:
if len(v.As) != 0 {
fmt.Fprintf(buf, "%s_%04d as %s",
sqlparser.String(v.Expr),
tableIndex,
string(v.As),
)
} else {
fmt.Fprintf(buf, "%s_%04d",
sqlparser.String(v.Expr),
tableIndex,
)
}
case *sqlparser.JoinTableExpr:
if ate, ok := (v.LeftExpr).(*sqlparser.AliasedTableExpr); ok {
if len(ate.As) != 0 {
fmt.Fprintf(buf, "%s_%04d as %s",
sqlparser.String(ate.Expr),
tableIndex,
string(ate.As),
)
} else {
fmt.Fprintf(buf, "%s_%04d",
sqlparser.String(ate.Expr),
tableIndex,
)
}
} else {
fmt.Fprintf(buf, "%s_%04d",
sqlparser.String(v.LeftExpr),
tableIndex,
)
}
buf.Fprintf(" %s %v", v.Join, v.RightExpr)
if v.On != nil {
buf.Fprintf(" on %v", v.On)
}
default:
fmt.Fprintf(buf, "%s_%04d",
sqlparser.String(node.From[0]),
tableIndex,
)
}
//append other tables
prefix := ", "
for i := 1; i < len(node.From); i++ {
buf.Fprintf("%s%v", prefix, node.From[i])
}
buf.Fprintf("%v%v%v%v%s",
node.Where,
node.GroupBy,
node.Having,
node.OrderBy,
node.Lock,
)
return buf.String()
}