Merge #41367

41367: sql: Add support for numeric JSON scalar casts r=rafiss a=chrisseto

* Fixes #41333
* Add support for queries such as
  - `SELECT '1'::jsonb::int`
  - `SELECT '1'::jsonb::float`
  - `SELECT '3.14'::jsonb::decimal`

Release note (sql change): Casting JSON numeric scalars to numeric
types now works as expected.

Co-authored-by: Chris Seto <chriskseto@gmail.com>

pkg/sql/sem/tree/casts.go

@@ -98,6 +98,7 @@ var validCasts = []castInfo{
  {from: types.IntervalFamily, to: types.IntFamily, volatility: VolatilityImmutable},
  {from: types.OidFamily, to: types.IntFamily, volatility: VolatilityImmutable},
  {from: types.BitFamily, to: types.IntFamily, volatility: VolatilityImmutable},
+ {from: types.JsonFamily, to: types.IntFamily, volatility: VolatilityImmutable},
 
  // Casts to FloatFamily.
  {from: types.UnknownFamily, to: types.FloatFamily, volatility: VolatilityImmutable},
@@ -111,6 +112,7 @@ var validCasts = []castInfo{
  {from: types.TimestampTZFamily, to: types.FloatFamily, volatility: VolatilityImmutable},
  {from: types.DateFamily, to: types.FloatFamily, volatility: VolatilityImmutable},
  {from: types.IntervalFamily, to: types.FloatFamily, volatility: VolatilityImmutable},
+ {from: types.JsonFamily, to: types.FloatFamily, volatility: VolatilityImmutable},
 
  // Casts to Box2D Family.
  {from: types.UnknownFamily, to: types.Box2DFamily, volatility: VolatilityImmutable},
@@ -150,6 +152,7 @@ var validCasts = []castInfo{
  {from: types.TimestampTZFamily, to: types.DecimalFamily, volatility: VolatilityImmutable},
  {from: types.DateFamily, to: types.DecimalFamily, volatility: VolatilityImmutable},
  {from: types.IntervalFamily, to: types.DecimalFamily, volatility: VolatilityImmutable},
+ {from: types.JsonFamily, to: types.DecimalFamily, volatility: VolatilityImmutable},
 
  // Casts to StringFamily.
  {from: types.UnknownFamily, to: types.StringFamily, volatility: VolatilityImmutable},
@@ -697,6 +700,13 @@ func performCastWithoutPrecisionTruncation(ctx *EvalContext, d Datum, t *types.T
  res = NewDInt(DInt(iv))
  case *DOid:
  res = &v.DInt
+ case *DJSON:
+ if dec, ok := v.AsDecimal(); ok {
+ asInt, err := dec.Int64()
+ if err == nil {
+ res = NewDInt(DInt(asInt))
+ }
+ }
  }
  if res != nil {
  return res, nil
@@ -747,6 +757,14 @@ func performCastWithoutPrecisionTruncation(ctx *EvalContext, d Datum, t *types.T
  return NewDFloat(DFloat(float64(v.UnixEpochDays()))), nil
  case *DInterval:
  return NewDFloat(DFloat(v.AsFloat64())), nil
+ case *DJSON:
+ if dec, ok := v.AsDecimal(); ok {
+ fl, err := dec.Float64()
+ if err != nil {
+ return nil, ErrFloatOutOfRange
+ }
+ return NewDFloat(DFloat(fl)), nil
+ }
  }
 
  case types.DecimalFamily:
@@ -795,6 +813,12 @@ func performCastWithoutPrecisionTruncation(ctx *EvalContext, d Datum, t *types.T
  case *DInterval:
  v.AsBigInt(&dd.Coeff)
  dd.Exponent = -9
+ case *DJSON:
+ if dec, ok := v.AsDecimal(); ok {
+ dd.Set(dec)
+ } else {
+ unset = false
+ }
  default:
  unset = true
  }

pkg/sql/sem/tree/testdata/eval/cast

@@ -1132,3 +1132,74 @@ eval
 'hello t'::string::char(100)
 ----
 'hello t'
+
+# Test that numeric jsonb values can be cast to a numeric data type
+eval
+'1'::jsonb::int
+----
+1
+
+eval
+'1'::jsonb::float
+----
+1.0
+
+eval
+'1'::jsonb::decimal
+----
+1
+
+eval
+'1'::jsonb::string
+----
+'1'
+
+eval
+'2.0'::jsonb::int
+----
+2
+
+eval
+'2.0'::jsonb::float
+----
+2.0
+
+eval
+'2.0'::jsonb::decimal
+----
+2.0
+
+eval
+'2.0'::jsonb::string
+----
+'2.0'
+
+eval
+'3.14'::jsonb::float
+----
+3.14
+
+eval
+'3.14'::jsonb::decimal
+----
+3.14
+
+eval
+'true'::jsonb::float
+----
+invalid cast: jsonb -> float
+
+eval
+'null'::jsonb::float
+----
+invalid cast: jsonb -> float
+
+eval
+'{}'::jsonb::float
+----
+invalid cast: jsonb -> float
+
+eval
+'[]'::jsonb::float
+----
+invalid cast: jsonb -> float

pkg/util/json/encoded.go

@@ -17,6 +17,7 @@ import (
  "strconv"
  "unsafe"
 
+ "github.com/cockroachdb/apd/v2"
  "github.com/cockroachdb/cockroach/pkg/sql/inverted"
  "github.com/cockroachdb/cockroach/pkg/util/syncutil"
  "github.com/cockroachdb/errors"
@@ -558,6 +559,18 @@ func (j *jsonEncoded) AsText() (*string, error) {
  return decoded.AsText()
 }
 
+func (j *jsonEncoded) AsDecimal() (*apd.Decimal, bool) {
+ if dec := j.alreadyDecoded(); dec != nil {
+ return dec.AsDecimal()
+ }
+
+ decoded, err := j.decode()
+ if err != nil {
+ return nil, false
+ }
+ return decoded.AsDecimal()
+}
+
 func (j *jsonEncoded) Compare(other JSON) (int, error) {
  if cmp := cmpJSONTypes(j.Type(), other.Type()); cmp != 0 {
  return cmp, nil

pkg/util/json/json.go

@@ -136,6 +136,10 @@ type JSON interface {
  // AsText returns the JSON document as a string, with quotes around strings removed, and null as nil.
  AsText() (*string, error)
 
+ // AsDecimal returns the JSON document as a apd.Decimal if it is a numeric
+ // type, and a boolean inidicating if this JSON document is a numeric type.
+ AsDecimal() (*apd.Decimal, bool)
+
  // Exists implements the `?` operator.
  Exists(string) (bool, error)
 
@@ -412,6 +416,17 @@ func (j jsonString) MaybeDecode() JSON { return j }
 func (j jsonArray) MaybeDecode() JSON { return j }
 func (j jsonObject) MaybeDecode() JSON { return j }
 
+func (j jsonNull) AsDecimal() (*apd.Decimal, bool) { return nil, false }
+func (j jsonFalse) AsDecimal() (*apd.Decimal, bool) { return nil, false }
+func (j jsonTrue) AsDecimal() (*apd.Decimal, bool) { return nil, false }
+func (j jsonString) AsDecimal() (*apd.Decimal, bool) { return nil, false }
+func (j jsonArray) AsDecimal() (*apd.Decimal, bool) { return nil, false }
+func (j jsonObject) AsDecimal() (*apd.Decimal, bool) { return nil, false }
+func (j jsonNumber) AsDecimal() (*apd.Decimal, bool) {
+ d := apd.Decimal(j)
+ return &d, true
+}
+
 func (j jsonNull) tryDecode() (JSON, error) { return j, nil }
 func (j jsonFalse) tryDecode() (JSON, error) { return j, nil }
 func (j jsonTrue) tryDecode() (JSON, error) { return j, nil }

pkg/util/json/json_test.go

@@ -2252,3 +2252,62 @@ func TestJSONRemovePath(t *testing.T) {
  }
  }
 }
+
+func TestToDecimal(t *testing.T) {
+ numericCases := []string{
+ "1",
+ "1.0",
+ "3.14",
+ "-3.14",
+ "1.000",
+ "-0.0",
+ "-0.09",
+ "0.08",
+ }
+
+ nonNumericCases := []string{
+ "\"1\"",
+ "{}",
+ "[]",
+ "true",
+ "false",
+ "null",
+ }
+
+ for _, tc := range numericCases {
+ t.Run(fmt.Sprintf("numeric - %s", tc), func(t *testing.T) {
+ dec1, _, err := apd.NewFromString(tc)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ json, err := ParseJSON(tc)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ dec2, ok := json.AsDecimal()
+ if !ok {
+ t.Fatalf("could not cast %v to decmial", json)
+ }
+
+ if dec1.Cmp(dec2) != 0 {
+ t.Fatalf("expected %s == %s", dec1.String(), dec2.String())
+ }
+ })
+ }
+
+ for _, tc := range nonNumericCases {
+ t.Run(fmt.Sprintf("nonNumeric - %s", tc), func(t *testing.T) {
+ json, err := ParseJSON(tc)
+ if err != nil {
+ t.Fatalf("expected no error")
+ }
+
+ dec, ok := json.AsDecimal()
+ if dec != nil || ok {
+ t.Fatalf("%v should not be a valid decimal", json)
+ }
+ })
+ }
+}