兼容field函数，方便实现自定义排序规则 (go-gorm#696)

Co-authored-by: Jinzhu <[email protected]>

field/expr.go

@@ -411,6 +411,10 @@ func (e expr) ifNull(value interface{}) expr {
 	return e.setE(clause.Expr{SQL: "IFNULL(?,?)", Vars: []interface{}{e.RawExpr(), value}})
 }
 
+func (e expr) field(value interface{}) expr {
+	return e.setE(clause.Expr{SQL: "FIELD(?, ?)", Vars: []interface{}{e.RawExpr(), value}, WithoutParentheses: true})
+}
+
 func (e expr) sum() expr {
 	return e.setE(clause.Expr{SQL: "SUM(?)", Vars: []interface{}{e.RawExpr()}})
 }

field/field.go

@@ -70,6 +70,11 @@ func (field Field) IfNull(value driver.Valuer) Expr {
 	return field.ifNull(value)
 }
 
+// Field ...
+func (field Field) Field(value []interface{}) Expr {
+	return field.field(value)
+}
+
 func (field Field) toSlice(values ...driver.Valuer) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {

field/float.go

@@ -115,6 +115,11 @@ func (field Float64) IfNull(value float64) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Float64) Filed(values ...float64) Float64 {
+	return Float64{field.field(values)}
+}
+
 func (field Float64) toSlice(values ...float64) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -236,6 +241,11 @@ func (field Float32) IfNull(value float32) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Float32) Filed(values ...float32) Float32 {
+	return Float32{field.field(values)}
+}
+
 func (field Float32) toSlice(values ...float32) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {

field/int.go

@@ -147,6 +147,11 @@ func (field Int) IfNull(value int) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Int) Filed(values ...int) Int {
+	return Int{field.field(values)}
+}
+
 func (field Int) toSlice(values ...int) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -298,6 +303,11 @@ func (field Int8) IfNull(value int8) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Int8) Filed(values ...int8) Int8 {
+	return Int8{field.field(values)}
+}
+
 func (field Int8) toSlice(values ...int8) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -449,6 +459,11 @@ func (field Int16) IfNull(value int16) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Int16) Filed(values ...int16) Int16 {
+	return Int16{field.field(values)}
+}
+
 func (field Int16) toSlice(values ...int16) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -600,6 +615,11 @@ func (field Int32) IfNull(value int32) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Int32) Filed(values ...int32) Int32 {
+	return Int32{field.field(values)}
+}
+
 func (field Int32) toSlice(values ...int32) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -751,6 +771,11 @@ func (field Int64) IfNull(value int64) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Int64) Filed(values ...int64) Int64 {
+	return Int64{field.field(values)}
+}
+
 func (field Int64) toSlice(values ...int64) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -902,6 +927,11 @@ func (field Uint) IfNull(value uint) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Uint) Filed(values ...uint) Uint {
+	return Uint{field.field(values)}
+}
+
 func (field Uint) toSlice(values ...uint) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -1053,6 +1083,11 @@ func (field Uint8) IfNull(value uint8) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Uint8) Filed(values ...uint8) Uint8 {
+	return Uint8{field.field(values)}
+}
+
 func (field Uint8) toSlice(values ...uint8) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -1204,6 +1239,11 @@ func (field Uint16) IfNull(value uint16) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Uint16) Filed(values ...uint16) Uint16 {
+	return Uint16{field.field(values)}
+}
+
 func (field Uint16) toSlice(values ...uint16) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -1355,6 +1395,11 @@ func (field Uint32) IfNull(value uint32) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Uint32) Filed(values ...uint32) Uint32 {
+	return Uint32{field.field(values)}
+}
+
 func (field Uint32) toSlice(values ...uint32) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {
@@ -1506,6 +1551,11 @@ func (field Uint64) IfNull(value uint64) Expr {
 	return field.ifNull(value)
 }
 
+// Filed ...
+func (field Uint64) Filed(values ...uint64) Uint64 {
+	return Uint64{field.field(values)}
+}
+
 func (field Uint64) toSlice(values ...uint64) []interface{} {
 	slice := make([]interface{}, len(values))
 	for i, v := range values {

field/string.go

@@ -123,6 +123,11 @@ func (field String) Concat(before, after string) String {
 	}
 }
 
+// Filed ...
+func (field String) Filed(values ...string) String {
+	return String{field.field(values)}
+}
+
 // SubstringIndex SUBSTRING_INDEX
 // https://dev.mysql.com/doc/refman/8.0/en/functions.html#function_substring-index
 func (field String) SubstringIndex(delim string, count int) String {
@@ -238,6 +243,11 @@ func (field Bytes) FindInSetWith(target string) Expr {
 	return expr{e: clause.Expr{SQL: "FIND_IN_SET(?,?)", Vars: []interface{}{target, field.RawExpr()}}}
 }
 
+// Filed ...
+func (field Bytes) Filed(values ...[]byte) Bytes {
+	return Bytes{field.field(values)}
+}
+
 // SubstringIndex SUBSTRING_INDEX
 // https://dev.mysql.com/doc/refman/8.0/en/functions.html#function_substring-index
 func (field Bytes) SubstringIndex(delim string, count int) Bytes {