clickhouse plugin - initial import

plugins/dbgate-plugin-clickhouse/src/backend/sql/columns.js

@@ -0,0 +1,12 @@
+module.exports = `
+select 
+    columns.table as "pureName",
+    tables.uuid as "objectId",
+    columns.name as "columnName",
+    columns.type as "dataType",
+    columns.comment as "columnComment"
+from system.columns 
+inner join system.tables on columns.table = tables.name and columns.database = tables.database
+where columns.database='#DATABASE#' and tables.uuid =OBJECT_ID_CONDITION
+order by toInt32(columns.position)
+`;