// See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_extract
func builtinExtract(args []types.Datum, _ context.Context) (d types.Datum, err error) {
unit := args[0].GetString()
vd := args[1]
if vd.Kind() == types.KindNull {
d.SetNull()
return d, nil
}
f := types.NewFieldType(mysql.TypeDatetime)
f.Decimal = mysql.MaxFsp
val, err := vd.ConvertTo(f)
if err != nil {
d.SetNull()
return d, errors.Trace(err)
}
if val.Kind() == types.KindNull {
d.SetNull()
return d, nil
}
if val.Kind() != types.KindMysqlTime {
err = errors.Errorf("need time type, but got %T", val)
d.SetNull()
return d, err
}
t := val.GetMysqlTime()
n, err1 := mysql.ExtractTimeNum(unit, t)
if err1 != nil {
d.SetNull()
return d, errors.Trace(err1)
}
d.SetInt64(n)
return d, nil
}
func (e *Evaluator) funcExtract(v *ast.FuncExtractExpr) bool {
val := v.Date.GetValue()
if val == nil {
v.SetValue(nil)
return true
}
f := types.NewFieldType(mysql.TypeDatetime)
f.Decimal = mysql.MaxFsp
var err error
val, err = types.Convert(val, f)
if err != nil {
e.err = errors.Trace(err)
return false
}
if val == nil {
v.SetValue(nil)
return true
}
t, ok := val.(mysql.Time)
if !ok {
e.err = ErrInvalidOperation.Gen("need time type, but got %T", val)
return false
}
n, err1 := mysql.ExtractTimeNum(v.Unit, t)
if err1 != nil {
e.err = errors.Trace(err1)
return false
}
v.SetValue(n)
return true
}
// Eval implements the Expression Eval interface.
func (e *Extract) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error) {
v, err := e.Date.Eval(ctx, args)
if v == nil || err != nil {
return nil, errors.Trace(err)
}
f := types.NewFieldType(mysql.TypeDatetime)
f.Decimal = mysql.MaxFsp
v, err = types.Convert(v, f)
if v == nil || err != nil {
return nil, errors.Trace(err)
}
t, ok := v.(mysql.Time)
if !ok {
return nil, errors.Errorf("need time type, but got %T", v)
}
n, err1 := mysql.ExtractTimeNum(e.Unit, t)
if err1 != nil {
return nil, errors.Trace(err1)
}
return n, nil
}