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ðŧ Microsoft SQL Server Cheat Codes
Microsoft SQL Server Cheat Codes
T-SQL Cheat Codes for TOP queries, APPLY operators, temp tables, and index DMV monitoring. 20 essential cheat codes ready to copy and execute.
# 1 SELECT TOP (N) DQL
Restrict returned rows in T-SQL.
Syntax:
SELECT TOP (n) col1 FROM dbo.tbl; Working Example:
SELECT TOP (10) OrderID, TotalAmount FROM dbo.Orders ORDER BY OrderDate DESC; # 2 WHERE DQL
Filter row outputs.
Syntax:
SELECT * FROM dbo.tbl WHERE col = val; Working Example:
SELECT * FROM dbo.Customers WHERE Country = 'USA'; # 3 JOIN Joins
Match records across T-SQL tables.
Syntax:
SELECT * FROM t1 JOIN t2 ON t1.id = t2.fk; Working Example:
SELECT c.CompanyName, o.OrderID FROM dbo.Customers c JOIN dbo.Orders o ON c.CustomerID = o.CustomerID; # 4 GROUP BY Aggregations
Group rows for aggregate totals.
Syntax:
SELECT col, COUNT(*) FROM dbo.tbl GROUP BY col; Working Example:
SELECT CustomerID, COUNT(*) AS OrderCount FROM dbo.Orders GROUP BY CustomerID; # 5 HAVING Aggregations
Filter aggregated groups.
Syntax:
SELECT col, SUM(val) FROM dbo.tbl GROUP BY col HAVING SUM(val) > 1000; Working Example:
SELECT CustomerID, SUM(TotalAmount) FROM dbo.Orders GROUP BY CustomerID HAVING SUM(TotalAmount) > 5000; # 6 INSERT INTO DML
Add new record into table.
Syntax:
INSERT INTO dbo.tbl (col) VALUES (val); Working Example:
INSERT INTO dbo.Categories (CategoryName) VALUES ('Hardware'); # 7 UPDATE SET DML
Modify column values.
Syntax:
UPDATE dbo.tbl SET col = val WHERE condition; Working Example:
UPDATE dbo.Products SET UnitPrice = UnitPrice * 1.05 WHERE CategoryID = 2; # 8 DELETE FROM DML
Remove records matching condition.
Syntax:
DELETE FROM dbo.tbl WHERE condition; Working Example:
DELETE FROM dbo.Logs WHERE LogDate < '2026-01-01'; # 9 MERGE INTO (UPSERT) DML
T-SQL MERGE statement upsert.
Syntax:
MERGE INTO dbo.Target t USING dbo.Source s ON (t.id = s.id) WHEN MATCHED THEN UPDATE SET t.val = s.val WHEN NOT MATCHED THEN INSERT (id, val) VALUES (s.id, s.val); Working Example:
MERGE INTO dbo.TargetUsers t USING dbo.SourceUsers s ON (t.UserID = s.UserID) WHEN MATCHED THEN UPDATE SET t.Email = s.Email WHEN NOT MATCHED THEN INSERT (UserID, Email) VALUES (s.UserID, s.Email); # 10 CROSS APPLY Joins
Invoke correlated table function per row.
Syntax:
SELECT * FROM t1 CROSS APPLY dbo.func(t1.id); Working Example:
SELECT c.CustomerID, o.OrderID FROM dbo.Customers c CROSS APPLY (SELECT TOP (1) OrderID FROM dbo.Orders WHERE CustomerID = c.CustomerID ORDER BY OrderDate DESC) o; # 11 OUTER APPLY Joins
Invoke correlated table function preserving NULLs.
Syntax:
SELECT * FROM t1 OUTER APPLY dbo.func(t1.id); Working Example:
SELECT c.CustomerID, o.OrderID FROM dbo.Customers c OUTER APPLY (SELECT TOP (1) OrderID FROM dbo.Orders WHERE CustomerID = c.CustomerID ORDER BY OrderDate DESC) o; # 12 STRING_AGG Aggregations
Concatenate text with specified separator.
Syntax:
SELECT STRING_AGG(col, ', ') WITHIN GROUP (ORDER BY col) FROM dbo.tbl GROUP BY grp; Working Example:
SELECT DepartmentID, STRING_AGG(FirstName, ', ') WITHIN GROUP (ORDER BY FirstName) FROM dbo.Employees GROUP BY DepartmentID; # 13 TRY_CAST / TRY_CONVERT Functions
Safely convert types returning NULL on failure.
Syntax:
SELECT TRY_CAST(col AS INT) FROM dbo.tbl; Working Example:
SELECT TRY_CAST(RawString AS INT) FROM dbo.StagingData; # 14 IDENTITY(1,1) Identity
Auto-generate unique numeric keys.
Syntax:
CREATE TABLE dbo.tbl (ID INT IDENTITY(1,1) PRIMARY KEY); Working Example:
CREATE TABLE dbo.Orders (OrderID INT IDENTITY(1,1) PRIMARY KEY, Total DECIMAL(18,2)); # 15 #temp local table Temp Tables
Create session-private temporary table.
Syntax:
CREATE TABLE #TempTable (id INT); Working Example:
CREATE TABLE #MonthlyStats (MonthID INT, TotalRev DECIMAL(18,2)); # 16 ##temp global table Temp Tables
Create global session-shared temporary table.
Syntax:
CREATE TABLE ##GlobalTemp (id INT); Working Example:
CREATE TABLE ##SharedCache (KeyID INT, Val VARCHAR(100)); # 17 ROW_NUMBER() OVER Window
Assign row index inside partition.
Syntax:
SELECT col, ROW_NUMBER() OVER(PARTITION BY grp ORDER BY val) FROM dbo.tbl; Working Example:
SELECT CustomerID, OrderID, ROW_NUMBER() OVER(PARTITION BY CustomerID ORDER BY OrderDate DESC) FROM dbo.Orders; # 18 PIVOT Analytics
Rotate row values into output columns.
Syntax:
SELECT * FROM (SELECT grp, col, val FROM dbo.tbl) PIVOT (SUM(val) FOR col IN ([A], [B])) pvt; Working Example:
SELECT Year, [1] AS Jan, [2] AS Feb FROM (SELECT YEAR(OrderDate) AS Year, MONTH(OrderDate) AS Month, Total FROM dbo.Orders) Src PIVOT (SUM(Total) FOR Month IN ([1], [2])) pvt; # 19 SET IDENTITY_INSERT Identity
Override automatic identity constraint for inserts.
Syntax:
SET IDENTITY_INSERT dbo.tbl ON; INSERT ... SET IDENTITY_INSERT dbo.tbl OFF; Working Example:
SET IDENTITY_INSERT dbo.Customers ON; INSERT INTO dbo.Customers (CustomerID, CompanyName) VALUES (999, 'Acme'); SET IDENTITY_INSERT dbo.Customers OFF; # 20 sys.dm_db_index_physical_stats DMV DBA
Inspect index fragmentation levels.
Syntax:
SELECT * FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'LIMITED'); Working Example:
SELECT object_name(object_id) AS TableName, avg_fragmentation_in_percent FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'LIMITED'); No cheat codes found matching your search term.