func (b *planBuilder) buildSelect(sel *ast.SelectStmt) Plan {
var aggFuncs []*ast.AggregateFuncExpr
hasAgg := b.detectSelectAgg(sel)
if hasAgg {
aggFuncs = b.extractSelectAgg(sel)
}
var p Plan
if sel.From != nil {
p = b.buildJoin(sel.From.TableRefs)
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
if sel.LockTp != ast.SelectLockNone {
p = b.buildSelectLock(p, sel.LockTp)
if b.err != nil {
return nil
}
}
if hasAgg {
p = b.buildAggregate(p, aggFuncs, sel.GroupBy)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
} else {
if hasAgg {
p = b.buildAggregate(p, aggFuncs, nil)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
}
if sel.OrderBy != nil {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
return p
}
func (b *planBuilder) buildSelect(sel *ast.SelectStmt) Plan {
var aggFuncs []*ast.AggregateFuncExpr
hasAgg := b.detectSelectAgg(sel)
if hasAgg {
aggFuncs = b.extractSelectAgg(sel)
}
// Build subquery
// Convert subquery to expr with plan
b.buildSubquery(sel)
var p Plan
if sel.From != nil {
p = b.buildFrom(sel)
if b.err != nil {
return nil
}
if sel.LockTp != ast.SelectLockNone {
p = b.buildSelectLock(p, sel.LockTp)
if b.err != nil {
return nil
}
}
if hasAgg {
p = b.buildAggregate(p, aggFuncs, sel.GroupBy)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
} else {
if hasAgg {
p = b.buildAggregate(p, aggFuncs, nil)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
}
if sel.Having != nil {
p = b.buildHaving(p, sel.Having)
if b.err != nil {
return nil
}
}
if sel.OrderBy != nil && !matchOrder(p, sel.OrderBy.Items) {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
return p
}
func (v *typeInferrer) selectStmt(x *ast.SelectStmt) {
rf := x.GetResultFields()
for _, val := range rf {
// column ID is 0 means it is not a real column from table, but a temporary column,
// so its type is not pre-defined, we need to set it.
if val.Column.ID == 0 && val.Expr.GetType() != nil {
val.Column.FieldType = *(val.Expr.GetType())
}
}
}
// Detect aggregate function or groupby clause.
func (b *planBuilder) detectSelectAgg(sel *ast.SelectStmt) bool {
if sel.GroupBy != nil {
return true
}
for _, f := range sel.GetResultFields() {
if ast.HasAggFlag(f.Expr) {
return true
}
}
return false
}
func (b *planBuilder) buildSelect(sel *ast.SelectStmt) Plan {
var p Plan
if sel.From != nil {
p = b.buildJoin(sel.From.TableRefs)
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
if sel.LockTp != ast.SelectLockNone {
p = b.buildSelectLock(p, sel.LockTp)
if b.err != nil {
return nil
}
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
} else {
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
}
if sel.OrderBy != nil {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
return p
}
// extractSelectAgg extracts aggregate functions and converts ColumnNameExpr to aggregate function.
func (b *planBuilder) extractSelectAgg(sel *ast.SelectStmt) []*ast.AggregateFuncExpr {
extractor := &ast.AggregateFuncExtractor{AggFuncs: make([]*ast.AggregateFuncExpr, 0)}
for _, f := range sel.GetResultFields() {
n, ok := f.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr!")
return nil
}
ve, ok := f.Expr.(*ast.ValueExpr)
if ok && len(f.Column.Name.O) > 0 {
agg := &ast.AggregateFuncExpr{
F: ast.AggFuncFirstRow,
Args: []ast.ExprNode{ve},
}
agg.SetType(ve.GetType())
extractor.AggFuncs = append(extractor.AggFuncs, agg)
n = agg
}
f.Expr = n.(ast.ExprNode)
}
// Extract agg funcs from having clause.
if sel.Having != nil {
n, ok := sel.Having.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from having clause")
return nil
}
sel.Having.Expr = n.(ast.ExprNode)
}
// Extract agg funcs from orderby clause.
if sel.OrderBy != nil {
for _, item := range sel.OrderBy.Items {
n, ok := item.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from orderby clause")
return nil
}
item.Expr = n.(ast.ExprNode)
// If item is PositionExpr, we need to rebind it.
// For PositionExpr will refer to a ResultField in fieldlist.
// After extract AggExpr from fieldlist, it may be changed (See the code above).
if pe, ok := item.Expr.(*ast.PositionExpr); ok {
pe.Refer = sel.GetResultFields()[pe.N-1]
}
}
}
return extractor.AggFuncs
}
// extractSelectAgg extracts aggregate functions and converts ColumnNameExpr to aggregate function.
func (b *planBuilder) extractSelectAgg(sel *ast.SelectStmt) []*ast.AggregateFuncExpr {
extractor := &ast.AggregateFuncExtractor{AggFuncs: make([]*ast.AggregateFuncExpr, 0)}
res := make([]*ast.ResultField, 0, len(sel.GetResultFields()))
for _, f := range sel.GetResultFields() {
n, ok := f.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr!")
return nil
}
ve, ok := f.Expr.(*ast.ValueExpr)
if ok && len(f.Column.Name.O) > 0 {
agg := &ast.AggregateFuncExpr{
F: ast.AggFuncFirstRow,
Args: []ast.ExprNode{ve},
}
extractor.AggFuncs = append(extractor.AggFuncs, agg)
n = agg
}
// Clone the ResultField.
// For "select c from t group by c;" both "c"s in select field and grouby clause refer to the same ResultField.
// So we should not affact the "c" in groupby clause.
nf := &ast.ResultField{
ColumnAsName: f.ColumnAsName,
Column: f.Column,
Table: f.Table,
DBName: f.DBName,
Expr: n.(ast.ExprNode),
}
res = append(res, nf)
}
sel.SetResultFields(res)
// Extract agg funcs from orderby clause.
if sel.OrderBy != nil {
for _, item := range sel.OrderBy.Items {
n, ok := item.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from orderby clause")
return nil
}
item.Expr = n.(ast.ExprNode)
}
}
// TODO: extract aggfuncs from having clause.
return extractor.AggFuncs
}
// extractSelectAgg extracts aggregate functions and converts ColumnNameExpr to aggregate function.
func (b *planBuilder) extractSelectAgg(sel *ast.SelectStmt) []*ast.AggregateFuncExpr {
extractor := &ast.AggregateFuncExtractor{AggFuncs: make([]*ast.AggregateFuncExpr, 0)}
res := make([]*ast.ResultField, 0, len(sel.GetResultFields()))
for _, f := range sel.GetResultFields() {
n, ok := f.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr!")
return nil
}
ve, ok := f.Expr.(*ast.ValueExpr)
if ok && len(f.Column.Name.O) > 0 {
agg := &ast.AggregateFuncExpr{
F: ast.AggFuncFirstRow,
Args: []ast.ExprNode{ve},
}
extractor.AggFuncs = append(extractor.AggFuncs, agg)
n = agg
}
// Clone the ResultField.
// For "select c from t group by c;" both "c"s in select field and grouby clause refer to the same ResultField.
// So we should not affact the "c" in groupby clause.
nf := &ast.ResultField{
ColumnAsName: f.ColumnAsName,
Column: f.Column,
Table: f.Table,
DBName: f.DBName,
Expr: n.(ast.ExprNode),
}
res = append(res, nf)
}
sel.SetResultFields(res)
// Extract agg funcs from having clause.
if sel.Having != nil {
n, ok := sel.Having.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from having clause")
return nil
}
sel.Having.Expr = n.(ast.ExprNode)
}
// Extract agg funcs from orderby clause.
if sel.OrderBy != nil {
for _, item := range sel.OrderBy.Items {
n, ok := item.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from orderby clause")
return nil
}
item.Expr = n.(ast.ExprNode)
// If item is PositionExpr, we need to rebind it.
// For PositionExpr will refer to a ResultField in fieldlist.
// After extract AggExpr from fieldlist, it may be changed (See the code above).
if pe, ok := item.Expr.(*ast.PositionExpr); ok {
pe.Refer = sel.GetResultFields()[pe.N-1]
}
}
}
return extractor.AggFuncs
}
// Detect aggregate function or groupby clause.
func (b *planBuilder) detectSelectAgg(sel *ast.SelectStmt) bool {
if sel.GroupBy != nil {
return true
}
for _, f := range sel.GetResultFields() {
if ast.HasAggFlag(f.Expr) {
return true
}
}
if sel.Having != nil {
if ast.HasAggFlag(sel.Having.Expr) {
return true
}
}
if sel.OrderBy != nil {
for _, item := range sel.OrderBy.Items {
if ast.HasAggFlag(item.Expr) {
return true
}
}
}
return false
}
func (b *planBuilder) buildSelect(sel *ast.SelectStmt) Plan {
// Detect aggregate function or groupby clause.
aggDetetor := &ast.AggFuncDetector{}
sel.Accept(aggDetetor)
var aggFuncs []*ast.AggregateFuncExpr
if aggDetetor.HasAggFunc {
extractor := &ast.AggregateFuncExtractor{AggFuncs: make([]*ast.AggregateFuncExpr, 0)}
// TODO: extract aggfuncs from having clause.
for _, f := range sel.GetResultFields() {
f.Expr.Accept(extractor)
// TODO: check error
}
aggFuncs = extractor.AggFuncs
// TODO: extract aggfuncs from having clause.
}
var p Plan
if sel.From != nil {
p = b.buildJoin(sel.From.TableRefs)
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
if sel.LockTp != ast.SelectLockNone {
p = b.buildSelectLock(p, sel.LockTp)
if b.err != nil {
return nil
}
}
if len(aggFuncs) > 0 {
p = b.buildAggregate(p, aggFuncs)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
} else {
if len(aggFuncs) > 0 {
p = b.buildAggregate(p, aggFuncs)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
}
if sel.OrderBy != nil {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
return p
}