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() }