fix(redshift): listcolumns doesn't return any results for views with …

…no schema binding (#91)

# Description
Using `SVV_COLUMNS` for listing column which supports local and external
tables and views, including [late-binding
views](https://docs.aws.amazon.com/redshift/latest/dg/r_CREATE_VIEW.html#r_CREATE_VIEW_late-binding-views).

## Linear Ticket
REV-1042

## Security
- [x] The code changed/added as part of this pull request won't create
any security issues with how the software is being used.

---------

Co-authored-by: Vikas Venkatraman <[email protected]>

sqlconnect/internal/redshift/db.go

@@ -54,6 +54,13 @@ func NewDB(credentialsJSON json.RawMessage) (*DB, error) {
 				cmds.SchemaExists = func(schema base.UnquotedIdentifier) string {
 					return fmt.Sprintf("SELECT schema_name FROM svv_redshift_schemas WHERE schema_name = '%[1]s'", schema)
 				}
+				cmds.ListColumns = func(catalog, schema, table base.UnquotedIdentifier) (string, string, string) {
+					stmt := fmt.Sprintf("SELECT column_name, data_type FROM SVV_COLUMNS WHERE table_schema = '%[1]s' AND table_name = '%[2]s'", schema, table)
+					if catalog != "" {
+						stmt += fmt.Sprintf(" AND table_catalog = '%[1]s'", catalog)
+					}
+					return stmt + " ORDER BY ordinal_position ASC", "column_name", "data_type"
+				}
 				return cmds
 			}),
 		),

sqlconnect/internal/redshift/testdata/legacy-column-mapping-test-columns-table.json

@@ -21,7 +21,7 @@
     "_character": "string",
     "_date": "datetime",
     "_time": "time without time zone",
-    "_timetz": "time with time zone",
+    "_timetz": "timetz",
     "_timestamptz": "datetime",
     "_timestampntz": "datetime",
     "_timestampwtz": "datetime",