Rewrite From (#30)

* add more test cases & replace some err in errors.New(...) style & add some built-in err types * update From & related test cases * add test cases & fix bug * fix issues

Author: BetaCat0

builder.go

@@ -43,6 +43,7 @@ type limit struct {
 type Builder struct {
 optype
 dialect string
+isNested bool
 tableName string
 subQuery *Builder
 cond Cond
@@ -69,12 +70,23 @@ func (b *Builder) Where(cond Cond) *Builder {
 return b
 }
 
-// From sets the name of table or the sub query's alias and itself
-func (b *Builder) From(tableName string, subQuery ...*Builder) *Builder {
-b.tableName = tableName
+// From sets from subject(can be a table name in string or a builder pointer) and its alias
+func (b *Builder) From(subject interface{}, alias ...string) *Builder {
+switch subject.(type) {
+case *Builder:
+b.subQuery = subject.(*Builder)
 
-if len(subQuery) > 0 {
-b.subQuery = subQuery[0]
+if len(alias) > 0 {
+b.tableName = alias[0]
+} else {
+b.isNested = true
+}
+case string:
+b.tableName = subject.(string)
+
+if len(alias) > 0 {
+b.tableName = b.tableName + " " + alias[0]
+}
 }
 
 return b

builder_b_test.go

@@ -149,7 +149,7 @@ func randQuery(dialect string, rgc *randGenConf) *Builder {
 }
 
 if isUnionized && rgc.allowLimit && rand.Intn(1000) >= 500 {
-b = randLimit(Dialect(dialect).Select().From("t", b))
+b = randLimit(Dialect(dialect).Select().From(b, "t"))
 }
 
 return b
@@ -198,7 +198,7 @@ func randSelectByCondition(dialect string, rgc *randGenConf) *Builder {
 if rgc.allowSubQuery {
 cpRgc := *rgc
 cpRgc.allowSubQuery = false
-b = Dialect(dialect).Select(randSelects()...).From(randTableName(0), randQuery(dialect, &cpRgc))
+b = Dialect(dialect).Select(randSelects()...).From(randQuery(dialect, &cpRgc), randTableName(0))
 } else {
 b = Dialect(dialect).Select(randSelects()...).From(randTableName(0))
 }

builder_limit.go

@@ -5,20 +5,19 @@
 package builder
 
 import (
-"errors"
 "fmt"
 "strings"
 )
 
 func (b *Builder) limitWriteTo(w Writer) error {
 if strings.TrimSpace(b.dialect) == "" {
-return errors.New("field `dialect` must be set up when performing LIMIT, try use `Dialect(dbType)` at first")
+return ErrDialectNotSetUp
 }
 
 if b.limitation != nil {
 limit := b.limitation
 if limit.offset < 0 || limit.limitN <= 0 {
-return errors.New("unexpected offset/limitN")
+return ErrInvalidLimitation
 }
 // erase limit condition
 b.limitation = nil
@@ -37,19 +36,19 @@ func (b *Builder) limitWriteTo(w Writer) error {
 var wb *Builder
 if b.optype == unionType {
 wb = Dialect(b.dialect).Select("at.*", "ROWNUM RN").
-From("at", b)
+From(b, "at")
 } else {
 wb = b
 }
 
 if limit.offset == 0 {
-final = Dialect(b.dialect).Select(selects...).From("at", wb).
+final = Dialect(b.dialect).Select(selects...).From(wb, "at").
 Where(Lte{"at.RN": limit.limitN})
 } else {
 sub := Dialect(b.dialect).Select("*").
-From("at", b).Where(Lte{"at.RN": limit.offset + limit.limitN})
+From(b, "at").Where(Lte{"at.RN": limit.offset + limit.limitN})
 
-final = Dialect(b.dialect).Select(selects...).From("att", sub).
+final = Dialect(b.dialect).Select(selects...).From(sub, "att").
 Where(Gt{"att.RN": limit.offset})
 }
 
@@ -78,15 +77,15 @@ func (b *Builder) limitWriteTo(w Writer) error {
 var wb *Builder
 if b.optype == unionType {
 wb = Dialect(b.dialect).Select("*", "ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS RN").
-From("at", b)
+From(b, "at")
 } else {
 wb = b
 }
 
 if limit.offset == 0 {
-final = Dialect(b.dialect).Select(selects...).From("at", wb)
+final = Dialect(b.dialect).Select(selects...).From(wb, "at")
 } else {
-final = Dialect(b.dialect).Select(selects...).From("at", wb).Where(Gt{"at.RN": limit.offset})
+final = Dialect(b.dialect).Select(selects...).From(wb, "at").Where(Gt{"at.RN": limit.offset})
 }
 
 return final.WriteTo(ow)

builder_limit_test.go

@@ -32,10 +32,10 @@ func TestBuilder_Limit4Mssql(t *testing.T) {
 assert.NoError(t, f.executableCheck(sql))
 
 // union with limit -- MsSQL style
-sql, err = Dialect(MSSQL).Select("a", "b", "c").From("at",
+sql, err = Dialect(MSSQL).Select("a", "b", "c").From(
 Dialect(MSSQL).Select("a", "b", "c").From("table1").Where(Neq{"a": "1"}).
 OrderBy("a ASC").Limit(5, 6).Union("ALL",
-Select("a", "b", "c").From("table1").Where(Neq{"b": "2"}).OrderBy("a DESC").Limit(10))).
+Select("a", "b", "c").From("table1").Where(Neq{"b": "2"}).OrderBy("a DESC").Limit(10)), "at").
 OrderBy("b DESC").Limit(7, 9).ToBoundSQL()
 assert.NoError(t, err)
 assert.EqualValues(t, "SELECT a,b,c FROM (SELECT TOP 16 a,b,c,ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS RN FROM ((SELECT a,b,c FROM (SELECT TOP 11 a,b,c,ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS RN FROM table1 WHERE a<>'1' ORDER BY a ASC) at WHERE at.RN>6) UNION ALL (SELECT a,b,c FROM (SELECT TOP 10 a,b,c,ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS RN FROM table1 WHERE b<>'2' ORDER BY a DESC) at)) at ORDER BY b DESC) at WHERE at.RN>9", sql)
@@ -71,10 +71,10 @@ func TestBuilder_Limit4MysqlLike(t *testing.T) {
 assert.NoError(t, f.executableCheck(sql))
 
 // union -- MySQL/SQLite/PostgreSQL style
-sql, err = Dialect(MYSQL).Select("a", "b", "c").From("at",
+sql, err = Dialect(MYSQL).Select("a", "b", "c").From(
 Dialect(MYSQL).Select("a", "b", "c").From("table1").Where(Eq{"a": "1"}).OrderBy("a ASC").
 Limit(5, 9).Union("ALL",
-Select("a", "b", "c").From("table1").Where(Eq{"a": "2"}).OrderBy("a DESC").Limit(10))).
+Select("a", "b", "c").From("table1").Where(Eq{"a": "2"}).OrderBy("a DESC").Limit(10)), "at").
 Limit(5, 10).ToBoundSQL()
 assert.NoError(t, err)
 assert.EqualValues(t, "SELECT a,b,c FROM ((SELECT a,b,c FROM table1 WHERE a='1' ORDER BY a ASC LIMIT 5 OFFSET 9) UNION ALL (SELECT a,b,c FROM table1 WHERE a='2' ORDER BY a DESC LIMIT 10)) at LIMIT 5 OFFSET 10", sql)
@@ -117,11 +117,11 @@ func TestBuilder_Limit4Oracle(t *testing.T) {
 assert.NoError(t, f.executableCheck(sql))
 
 // union with limit -- OracleSQL style
-sql, err = Dialect(ORACLE).Select("a", "b", "c").From("at",
+sql, err = Dialect(ORACLE).Select("a", "b", "c").From(
 Dialect(ORACLE).Select("a", "b", "c").From("table1").
 Where(Neq{"a": "0"}).OrderBy("a ASC").Limit(5, 10).Union("ALL",
 Select("a", "b", "c").From("table1").Where(Neq{"b": "48"}).
-OrderBy("a DESC").Limit(10))).
+OrderBy("a DESC").Limit(10)), "at").
 Limit(3).ToBoundSQL()
 assert.NoError(t, err)
 assert.EqualValues(t, "SELECT a,b,c FROM (SELECT a,b,c,ROWNUM RN FROM ((SELECT a,b,c FROM (SELECT * FROM (SELECT a,b,c,ROWNUM RN FROM table1 WHERE a<>'0' ORDER BY a ASC) at WHERE at.RN<=15) att WHERE att.RN>10) UNION ALL (SELECT a,b,c FROM (SELECT a,b,c,ROWNUM RN FROM table1 WHERE b<>'48' ORDER BY a DESC) at WHERE at.RN<=10)) at) at WHERE at.RN<=3", sql)

builder_select.go

@@ -5,7 +5,6 @@
 package builder
 
 import (
-"errors"
 "fmt"
 )
 
@@ -16,7 +15,7 @@ func Select(cols ...string) *Builder {
 }
 
 func (b *Builder) selectWriteTo(w Writer) error {
-if len(b.tableName) <= 0 {
+if len(b.tableName) <= 0 && !b.isNested {
 return ErrNoTableName
 }
 
@@ -26,12 +25,6 @@ func (b *Builder) selectWriteTo(w Writer) error {
 return b.limitWriteTo(w)
 }
 
-// perform limit before writing to writer when b.dialect between ORACLE and MSSQL
-// this avoid a duplicate writing problem in simple limit query
-if b.limitation != nil && (b.dialect == ORACLE || b.dialect == MSSQL) {
-return b.limitWriteTo(w)
-}
-
 if _, err := fmt.Fprint(w, "SELECT "); err != nil {
 return err
 }
@@ -57,6 +50,10 @@ func (b *Builder) selectWriteTo(w Writer) error {
 return err
 }
 } else {
+if b.cond.IsValid() && len(b.tableName) <= 0 {
+return ErrUnnamedDerivedTable
+}
+
 switch b.subQuery.optype {
 case selectType, unionType:
 fmt.Fprint(w, " FROM (")
@@ -70,7 +67,7 @@ func (b *Builder) selectWriteTo(w Writer) error {
 fmt.Fprintf(w, ") %v", b.tableName)
 }
 default:
-return errors.New("SubQuery is limited in SELECT and UNION")
+return ErrUnexpectedSubQuery
 }
 }
 

builder_select_test.go

@@ -77,23 +77,46 @@ func TestBuilder_From(t *testing.T) {
 assert.EqualValues(t, "SELECT c FROM table1", sql)
 assert.EqualValues(t, 0, len(args))
 
-// from sub
-sql, args, err = Select("sub.id").From("sub",
-Select("id").From("table1").Where(Eq{"a": 1})).Where(Eq{"b": 1}).ToSQL()
+// from sub with alias
+sql, args, err = Select("sub.id").From(Select("id").From("table1").Where(Eq{"a": 1}),
+"sub").Where(Eq{"b": 1}).ToSQL()
 assert.NoError(t, err)
 assert.EqualValues(t, "SELECT sub.id FROM (SELECT id FROM table1 WHERE a=?) sub WHERE b=?", sql)
 assert.EqualValues(t, []interface{}{1, 1}, args)
 
-// from union
-sql, args, err = Select("sub.id").From("sub",
-Select("id").From("table1").Where(Eq{"a": 1}).
-Union("all", Select("id").From("table1").Where(Eq{"a": 2}))).Where(Eq{"b": 1}).ToSQL()
+// from sub without alias and with conditions
+sql, args, err = Select("sub.id").From(Select("id").From("table1").Where(Eq{"a": 1})).Where(Eq{"b": 1}).ToSQL()
+assert.Error(t, err)
+assert.EqualValues(t, ErrUnnamedDerivedTable, err)
+
+// from sub without alias and conditions
+sql, args, err = Select("sub.id").From(Select("id").From("table1").Where(Eq{"a": 1})).ToSQL()
+assert.NoError(t, err)
+assert.EqualValues(t, "SELECT sub.id FROM (SELECT id FROM table1 WHERE a=?)", sql)
+assert.EqualValues(t, []interface{}{1}, args)
+
+// from union with alias
+sql, args, err = Select("sub.id").From(
+Select("id").From("table1").Where(Eq{"a": 1}).Union(
+"all", Select("id").From("table1").Where(Eq{"a": 2})), "sub").Where(Eq{"b": 1}).ToSQL()
 assert.NoError(t, err)
 assert.EqualValues(t, "SELECT sub.id FROM ((SELECT id FROM table1 WHERE a=?) UNION ALL (SELECT id FROM table1 WHERE a=?)) sub WHERE b=?", sql)
 assert.EqualValues(t, []interface{}{1, 2, 1}, args)
 
+// from union without alias
+sql, args, err = Select("sub.id").From(
+Select("id").From("table1").Where(Eq{"a": 1}).Union(
+"all", Select("id").From("table1").Where(Eq{"a": 2}))).Where(Eq{"b": 1}).ToSQL()
+assert.Error(t, err)
+assert.EqualValues(t, ErrUnnamedDerivedTable, err)
+
+// will raise error
+sql, args, err = Select("c").From(Insert(Eq{"a": 1}).From("table1"), "table1").ToSQL()
+assert.Error(t, err)
+assert.EqualValues(t, ErrUnexpectedSubQuery, err)
+
 // will raise error
-sql, args, err = Select("c").From("table1", Insert(Eq{"a": 1}).From("table1")).ToSQL()
+sql, args, err = Select("c").From(Delete(Eq{"a": 1}).From("table1"), "table1").ToSQL()
 assert.Error(t, err)
-fmt.Println(err)
+assert.EqualValues(t, ErrUnexpectedSubQuery, err)
 }

builder_union.go

@@ -10,7 +10,7 @@ import (
 )
 
 func (b *Builder) unionWriteTo(w Writer) error {
-if b.limitation != nil || b.cond != NewCond() ||
+if b.limitation != nil || b.cond.IsValid() ||
 b.orderBy != "" || b.having != "" || b.groupBy != "" {
 return ErrNotUnexpectedUnionConditions
 }

error.go

@@ -27,4 +27,12 @@ var (
 ErrNotUnexpectedUnionConditions = errors.New("Unexpected conditional fields in UNION query")
 // ErrUnsupportedUnionMembers unexpected members in UNION query
 ErrUnsupportedUnionMembers = errors.New("Unexpected members in UNION query")
+// ErrUnexpectedSubQuery Unexpected sub-query in SELECT query
+ErrUnexpectedSubQuery = errors.New("Unexpected sub-query in SELECT query")
+// ErrDialectNotSetUp dialect is not setup yet
+ErrDialectNotSetUp = errors.New("Dialect is not setup yet, try to use `Dialect(dbType)` at first")
+// ErrInvalidLimitation offset or limit is not correct
+ErrInvalidLimitation = errors.New("Offset or limit is not correct")
+// ErrUnnamedDerivedTable Every derived table must have its own alias
+ErrUnnamedDerivedTable = errors.New("Every derived table must have its own alias")
 )

sql_test.go

@@ -157,5 +157,4 @@ func TestExecutableCheck(t *testing.T) {
 
 err = f.executableCheck("SELECT * FROM table3")
 assert.Error(t, err)
-fmt.Println(err)
 }