From 433efbe1029cfd8200858f77aa40cd3a62a1c441 Mon Sep 17 00:00:00 2001
From: chad <example@qq.com>
Date: Sat, 12 Jun 2021 16:35:08 +0800
Subject: [PATCH 1/2] fix pg GetColumns missing comment

---
 dialects/postgres.go | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/dialects/postgres.go b/dialects/postgres.go
index 52c88567..9acf763a 100644
--- a/dialects/postgres.go
+++ b/dialects/postgres.go
@@ -1044,12 +1044,13 @@ func (db *postgres) IsColumnExist(queryer core.Queryer, ctx context.Context, tab
 
 func (db *postgres) GetColumns(queryer core.Queryer, ctx context.Context, tableName string) ([]string, map[string]*schemas.Column, error) {
 	args := []interface{}{tableName}
-	s := `SELECT column_name, column_default, is_nullable, data_type, character_maximum_length,
+	s := `SELECT column_name, column_default, is_nullable, data_type, character_maximum_length, description,
     CASE WHEN p.contype = 'p' THEN true ELSE false END AS primarykey,
     CASE WHEN p.contype = 'u' THEN true ELSE false END AS uniquekey
 FROM pg_attribute f
     JOIN pg_class c ON c.oid = f.attrelid JOIN pg_type t ON t.oid = f.atttypid
     LEFT JOIN pg_attrdef d ON d.adrelid = c.oid AND d.adnum = f.attnum
+    LEFT JOIN pg_description de ON f.attrelid=de.objoid AND f.attnum=de.objsubid
     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
     LEFT JOIN pg_constraint p ON p.conrelid = c.oid AND f.attnum = ANY (p.conkey)
     LEFT JOIN pg_class AS g ON p.confrelid = g.oid
@@ -1078,9 +1079,9 @@ WHERE n.nspname= s.table_schema AND c.relkind = 'r'::char AND c.relname = $1%s A
 		col.Indexes = make(map[string]int)
 
 		var colName, isNullable, dataType string
-		var maxLenStr, colDefault *string
+		var maxLenStr, colDefault, description *string
 		var isPK, isUnique bool
-		err = rows.Scan(&colName, &colDefault, &isNullable, &dataType, &maxLenStr, &isPK, &isUnique)
+		err = rows.Scan(&colName, &colDefault, &isNullable, &dataType, &maxLenStr, &description, &isPK, &isUnique)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -1126,6 +1127,10 @@ WHERE n.nspname= s.table_schema AND c.relkind = 'r'::char AND c.relname = $1%s A
 			col.DefaultIsEmpty = true
 		}
 
+		if description != nil {
+			col.Comment = *description
+		}
+
 		if isPK {
 			col.IsPrimaryKey = true
 		}
-- 
2.40.1


From 8ea8ef929cbbb634bff9662b6a889ebe82e0af34 Mon Sep 17 00:00:00 2001
From: chad <example@qq.com>
Date: Sat, 12 Jun 2021 19:15:11 +0800
Subject: [PATCH 2/2] add test

---
 integrations/engine_test.go | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/integrations/engine_test.go b/integrations/engine_test.go
index 9b70f9b5..f3991f0f 100644
--- a/integrations/engine_test.go
+++ b/integrations/engine_test.go
@@ -209,3 +209,39 @@ func TestDBVersion(t *testing.T) {
 
 	fmt.Println(testEngine.Dialect().URI().DBType, "version is", version)
 }
+
+func TestGetColumns(t *testing.T) {
+	if testEngine.Dialect().URI().DBType != schemas.POSTGRES {
+		t.Skip()
+		return
+	}
+	type TestCommentStruct struct {
+		HasComment int
+		NoComment  int
+	}
+
+	assertSync(t, new(TestCommentStruct))
+
+	comment := "this is a comment"
+	sql := fmt.Sprintf("comment on column %s.%s is '%s'", testEngine.TableName(new(TestCommentStruct), true), "has_comment", comment)
+	_, err := testEngine.Exec(sql)
+	assert.NoError(t, err)
+
+	tables, err := testEngine.DBMetas()
+	assert.NoError(t, err)
+	tableName := testEngine.GetColumnMapper().Obj2Table("TestCommentStruct")
+	var hasComment, noComment string
+	for _, table := range tables {
+		if table.Name == tableName {
+			col := table.GetColumn("has_comment")
+			assert.NotNil(t, col)
+			hasComment = col.Comment
+			col2 := table.GetColumn("no_comment")
+			assert.NotNil(t, col2)
+			noComment = col2.Comment
+			break
+		}
+	}
+	assert.Equal(t, comment, hasComment)
+	assert.Zero(t, noComment)
+}
-- 
2.40.1