Assign identical ID to duplicates in SQL server

Question

I would like to create an update query that would assign incremental IDs to values in my table. However, duplicate values should receive the same ID.

MyTable:

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Answer 1

You can create a table with an auto increment id field an the word.

MySQL:

CREATE TABLE secondTable (
id  int NOT NULL AUTO_INCREMENT,
word  varchar(255) NULL,
PRIMARY KEY (id)
);

MSSQL:

CREATE TABLE [secondTable] (
[id] int NOT NULL IDENTITY(1,1) ,
[word] varchar NULL ,
PRIMARY KEY ([id])
)

After that you insert the distinct values of word in your secondTable.

INSERT INTO secondTable (word) SELECT distinct word FROM MyTable;

At last you can update your table with the grouping IDs:

UPDATE MyTable 
SET ID = (SELECT id from secondTable where MyTable.word = secondTable.word)