Fix for query folding issue with direct query mode in Power BI data connector (#640)

* pbi connector

* update names

* - add mez file
- add docs

* nit

* nit

* image resize

* resize image

* remove extra lines

* nit

* update mez file

* rename connector

* rename mez file

* - add basic & aws auth
- add unit test
- add errors
- enable direct query

* add connector

* update doc

* add ssl for auth

* update docs for errors

* - remove sqlgetinfo & sqlcapabilities values from connector

* adding EncryptedConnectionString

* add data type for columns

* add alternate column size

* reverting changes in catalog test

* nit

* revert changes for column size validation

* address PR comments

* Update SQL_GROUP_BY value for fixing query folding issue

* removing AstVisitor for resolving query folding issue with data type boolean

Author: rupal-bq

sql-odbc/src/IntegrationTests/ITODBCInfo/test_odbc_info.cpp

@@ -180,7 +180,7 @@ TEST_SQL_GET_INFO_VERSION_GE(SQLDBMSVer, SQL_DBMS_VER, L"7.1.1");
 
 TEST_SQL_GET_INFO_STRING(SQLColumnAlias, SQL_COLUMN_ALIAS, L"Y");
 TEST_SQL_GET_INFO_UINT16(SQLGroupBy, SQL_GROUP_BY,
-                         SQL_GB_GROUP_BY_EQUALS_SELECT);
+                         SQL_GB_GROUP_BY_CONTAINS_SELECT);
 TEST_SQL_GET_INFO_STRING(SQLIdentifierQuoteChar, SQL_IDENTIFIER_QUOTE_CHAR,
                          L"`");
 TEST_SQL_GET_INFO_UINT_MASK(SQLOJCapabilities, SQL_OJ_CAPABILITIES,

sql-odbc/src/PowerBIConnector/OdfeSqlOdbcPBIConnector.pq

@@ -78,6 +78,10 @@ OdfeSqlOdbcPBIConnectorImpl = (Host as text, optional Port as number) as table =
             Driver = "ODFE SQL ODBC Driver"
         ],
 
+        SQLGetInfo = Diagnostics.LogValue("SQLGetInfo_Options", [
+            SQL_AGGREGATE_FUNCTIONS = ODBC[SQL_AF][All]
+        ]),
+
         SQLGetTypeInfo = (types) => 
             if (EnableTraceOutput <> true) then types else
             let
@@ -102,26 +106,6 @@ OdfeSqlOdbcPBIConnectorImpl = (Host as text, optional Port as number) as table =
                     Value.ReplaceType(toTable, Value.Type(source))
             else
                 source,
-             
-        // Add support for `LIMIT` and `OFFSET` clauses (rather than `TOP`)
-        AstVisitor = [
-            // format is "LIMIT [<skip>,]<take>" - ex. LIMIT 2,10 or LIMIT 10
-            LimitClause = (skip, take) =>
-                if (take = null) then
-                    ...
-                else
-                    let
-                        skip =
-                            if (skip = null or skip = 0) then
-                                ""
-                            else
-                                Number.ToText(skip) & ","
-                    in
-                        [
-                            Text = Text.Format("LIMIT #{0}#{1}", { skip, take }),
-                            Location = "AfterQuerySpecification"
-                        ]
-        ],
 
         OdbcDatasource = Odbc.DataSource(ConnectionString & Server & CredentialConnectionString & EncryptedConnectionString, [
             // Do not view the tables grouped by their schema names.
@@ -136,9 +120,9 @@ OdfeSqlOdbcPBIConnectorImpl = (Host as text, optional Port as number) as table =
             ClientConnectionPooling = true,
 
             // These values should be set by previous steps
-            AstVisitor = AstVisitor,
             SQLColumns = SQLColumns,
             SQLGetTypeInfo = SQLGetTypeInfo,
+            SQLGetInfo = SQLGetInfo,
 
             OnError = OnOdbcError,
 

sql-odbc/src/PowerBIConnector/bin/Release/OdfeSqlOdbcPBIConnector.mez

@@ -245,7 +245,7 @@ RETCODE SQL_API ESAPI_GetInfo(HDBC hdbc, SQLUSMALLINT fInfoType,
 
         case SQL_GROUP_BY: /* ODBC 2.0 */
             len = 2;
-            value = SQL_GB_GROUP_BY_EQUALS_SELECT;
+            value = SQL_GB_GROUP_BY_CONTAINS_SELECT;
             break;
 
         case SQL_IDENTIFIER_CASE: /* ODBC 1.0 */