From 6064f9f20190a5ce027495f42e90752cddad7aa3 Mon Sep 17 00:00:00 2001
From: Wing-Kam Wong <wingkwong.code@gmail.com>
Date: Mon, 18 Jul 2022 13:42:07 +0800
Subject: [PATCH] feat: WEEKDAY logic for mssql

---
 .../lib/sql/functionMappings/mssql.ts          | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/packages/nocodb/src/lib/db/sql-data-mapper/lib/sql/functionMappings/mssql.ts b/packages/nocodb/src/lib/db/sql-data-mapper/lib/sql/functionMappings/mssql.ts
index a95f69e6c4..78c4f5c142 100644
--- a/packages/nocodb/src/lib/db/sql-data-mapper/lib/sql/functionMappings/mssql.ts
+++ b/packages/nocodb/src/lib/db/sql-data-mapper/lib/sql/functionMappings/mssql.ts
@@ -108,6 +108,24 @@ const mssql = {
       END${colAlias}`
     );
   },
+  WEEKDAY: ({ fn, knex, pt, colAlias }: MapFnArgs) => {
+    // DATEPART(WEEKDAY, DATE): sunday = 1, monday = 2, ..., saturday = 7
+    // WEEKDAY() returns an index from 0 to 6 for Monday to Sunday
+    const m = {
+      monday: 0,
+      tuesday: 1,
+      wednesday: 2,
+      thursday: 3,
+      friday: 4,
+      saturday: 5,
+      sunday: 6,
+    };
+    return knex.raw(
+      `(DATEPART(WEEKDAY, ${fn(pt.arguments[0])}) - 2 - ${
+        m[pt?.arguments[1]?.value.toLowerCase()] || 0
+      } % 7 + 7) % 7 ${colAlias}`
+    );
+  },
 };
 
 export default mssql;