Issue #203

* [ADDED] Support for getting column identifiers from AliasExpressions. #203
doug-martin · Mar 20, 2020 · 417f438 · 417f438
1 parent a8f0c36
commit 417f438
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Showing 7 changed files with 173 additions and 2 deletions.
diff --git a/HISTORY.md b/HISTORY.md
@@ -2,6 +2,7 @@
 
 * [ADDED] Support for ANY and ALL operators. [#196](https://github.com/doug-martin/goqu/issues/196)
 * [ADDED] Support for CASE statements [#193](https://github.com/doug-martin/goqu/issues/193) 
+* [ADDED] Support for getting column identifiers from AliasExpressions. [#203](https://github.com/doug-martin/goqu/issues/203)  
 
 # v9.7.1
 

diff --git a/exp/alias.go b/exp/alias.go
@@ -36,3 +36,24 @@ func (ae aliasExpression) Aliased() Expression {
 func (ae aliasExpression) GetAs() IdentifierExpression {
 	return ae.alias
 }
+
+// Returns a new IdentifierExpression with the specified schema
+func (ae aliasExpression) Schema(schema string) IdentifierExpression {
+	return ae.alias.Schema(schema)
+}
+
+// Returns a new IdentifierExpression with the specified table
+func (ae aliasExpression) Table(table string) IdentifierExpression {
+	return ae.alias.Table(table)
+}
+
+// Returns a new IdentifierExpression with the specified column
+func (ae aliasExpression) Col(col interface{}) IdentifierExpression {
+	return ae.alias.Col(col)
+}
+
+// Returns a new IdentifierExpression with the column set to *
+//   I("my_table").As("t").All() //"t".*
+func (ae aliasExpression) All() IdentifierExpression {
+	return ae.alias.All()
+}
diff --git a/exp/alias_test.go b/exp/alias_test.go
@@ -0,0 +1,68 @@
+package exp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type aliasExpressionSuite struct {
+	suite.Suite
+}
+
+func TestAliasExpressionSuite(t *testing.T) {
+	suite.Run(t, &aliasExpressionSuite{})
+}
+
+func (aes *aliasExpressionSuite) TestClone() {
+	ae := aliased(NewIdentifierExpression("", "", "col"), "c")
+	aes.Equal(ae, ae.Clone())
+}
+
+func (aes *aliasExpressionSuite) TestExpression() {
+	ae := aliased(NewIdentifierExpression("", "", "col"), "c")
+	aes.Equal(ae, ae.Expression())
+}
+
+func (aes *aliasExpressionSuite) TestAliased() {
+	ident := NewIdentifierExpression("", "", "col")
+	ae := aliased(ident, "c")
+	aes.Equal(ident, ae.Aliased())
+}
+
+func (aes *aliasExpressionSuite) TestGetAs() {
+	ae := aliased(NewIdentifierExpression("", "", "col"), "c")
+	aes.Equal(NewIdentifierExpression("", "", "c"), ae.GetAs())
+}
+
+func (aes *aliasExpressionSuite) TestSchema() {
+	si := aliased(
+		NewIdentifierExpression("", "t", nil),
+		NewIdentifierExpression("", "t", nil),
+	).Schema("s")
+	aes.Equal(NewIdentifierExpression("s", "t", nil), si)
+}
+
+func (aes *aliasExpressionSuite) TestTable() {
+	si := aliased(
+		NewIdentifierExpression("schema", "", nil),
+		NewIdentifierExpression("s", "", nil),
+	).Table("t")
+	aes.Equal(NewIdentifierExpression("s", "t", nil), si)
+}
+
+func (aes *aliasExpressionSuite) TestCol() {
+	si := aliased(
+		NewIdentifierExpression("", "table", nil),
+		NewIdentifierExpression("", "t", nil),
+	).Col("c")
+	aes.Equal(NewIdentifierExpression("", "t", "c"), si)
+}
+
+func (aes *aliasExpressionSuite) TestAll() {
+	si := aliased(
+		NewIdentifierExpression("", "table", nil),
+		NewIdentifierExpression("", "t", nil),
+	).All()
+	aes.Equal(NewIdentifierExpression("", "t", Star()), si)
+}
diff --git a/exp/exp.go b/exp/exp.go
@@ -172,6 +172,16 @@ type (
 		Aliased() Expression
 		// Returns the alias value as an identiier expression
 		GetAs() IdentifierExpression
+
+		// Returns a new IdentifierExpression with the specified schema
+		Schema(string) IdentifierExpression
+		// Returns a new IdentifierExpression with the specified table
+		Table(string) IdentifierExpression
+		// Returns a new IdentifierExpression with the specified column
+		Col(interface{}) IdentifierExpression
+		// Returns a new IdentifierExpression with the column set to *
+		//   I("my_table").All() //"my_table".*
+		All() IdentifierExpression
 	}
 
 	BooleanOperation  int

diff --git a/exp/ident.go b/exp/ident.go
@@ -1,6 +1,8 @@
 package exp
 
-import "strings"
+import (
+	"strings"
+)
 
 type (
 	identifier struct {
@@ -117,7 +119,21 @@ func (i identifier) GetCol() interface{} { return i.col }
 func (i identifier) Set(val interface{}) UpdateExpression { return set(i, val) }
 
 // Alias an identifier (e.g "my_col" AS "other_col")
-func (i identifier) As(val interface{}) AliasedExpression { return aliased(i, val) }
+func (i identifier) As(val interface{}) AliasedExpression {
+	if v, ok := val.(string); ok {
+		ident := ParseIdentifier(v)
+		if i.col != nil && i.col != "" {
+			return aliased(i, ident)
+		}
+		aliasCol := ident.GetCol()
+		if i.table != "" {
+			return aliased(i, NewIdentifierExpression("", aliasCol.(string), nil))
+		} else if i.schema != "" {
+			return aliased(i, NewIdentifierExpression(aliasCol.(string), "", nil))
+		}
+	}
+	return aliased(i, val)
+}
 
 // Returns a BooleanExpression for equality (e.g "my_col" = 1)
 func (i identifier) Eq(val interface{}) BooleanExpression { return eq(i, val) }

diff --git a/exp/ident_test.go b/exp/ident_test.go
@@ -165,6 +165,33 @@ func (ies *identifierExpressionSuite) TestIsEmpty() {
 	}
 }
 
+func (ies *identifierExpressionSuite) TestAs() {
+	cases := []struct {
+		Alias    AliasedExpression
+		Expected Expression
+	}{
+		{
+			Alias:    NewIdentifierExpression("", "", "col").As("c"),
+			Expected: aliased(NewIdentifierExpression("", "", "col"), NewIdentifierExpression("", "", "c")),
+		},
+		{
+			Alias:    NewIdentifierExpression("", "table", nil).As("t"),
+			Expected: aliased(NewIdentifierExpression("", "table", nil), NewIdentifierExpression("", "t", nil)),
+		},
+		{
+			Alias:    NewIdentifierExpression("", "table", nil).As("s.t"),
+			Expected: aliased(NewIdentifierExpression("", "table", nil), NewIdentifierExpression("", "t", nil)),
+		},
+		{
+			Alias:    NewIdentifierExpression("schema", "", nil).As("s"),
+			Expected: aliased(NewIdentifierExpression("schema", "", nil), NewIdentifierExpression("s", "", nil)),
+		},
+	}
+	for _, tc := range cases {
+		ies.Equal(tc.Expected, tc.Alias)
+	}
+}
+
 func (ies *identifierExpressionSuite) TestAllOthers() {
 	ident := NewIdentifierExpression("", "", "a")
 	rv := NewRangeVal(1, 2)

diff --git a/issues_test.go b/issues_test.go
@@ -422,6 +422,34 @@ func (gis *githubIssuesSuite) TestIssue185() {
 	gis.Equal([]int{1, 2, 3, 4}, i)
 }
 
+// Test for https://github.com/doug-martin/goqu/issues/203
+func (gis *githubIssuesSuite) TestIssue203() {
+	// Schema definitions.
+	authSchema := goqu.S("company_auth")
+
+	// Table definitions
+	usersTable := authSchema.Table("users")
+
+	u := usersTable.As("u")
+
+	ds := goqu.From(u).Select(
+		u.Col("id"),
+		u.Col("name"),
+		u.Col("created_at"),
+		u.Col("updated_at"),
+	)
+
+	sql, args, err := ds.ToSQL()
+	gis.NoError(err)
+	gis.Equal(`SELECT "u"."id", "u"."name", "u"."created_at", "u"."updated_at" FROM "company_auth"."users" AS "u"`, sql)
+	gis.Empty(args, []interface{}{})
+
+	sql, args, err = ds.Prepared(true).ToSQL()
+	gis.NoError(err)
+	gis.Equal(`SELECT "u"."id", "u"."name", "u"."created_at", "u"."updated_at" FROM "company_auth"."users" AS "u"`, sql)
+	gis.Empty(args, []interface{}{})
+}
+
 func TestGithubIssuesSuite(t *testing.T) {
 	suite.Run(t, new(githubIssuesSuite))
 }