Sql 查询选择前 3 个字符

Question

I am trying to select the records from 2 tables in which the 1st table column named DESC (first 3 characters) should match with the project column of the 2nd table.

select SUBSTRING(a.[DESC],1,3) from Table1 a
left outer join Table2 b
on a.[DESC] = b.project
where SUBSTRING(a.[DESC],1,3) like b.project

Input: 1st Table DESC Column: Value: '2AB F YY'

2nd Table Project Column: Value: '2AB'

Expected Output: Return all the records of value 2AB

Answer 1

select SUBSTRING(a.[DESC],1,3),* from Table1 a
join Table2 b
on SUBSTRING(a.[DESC],1,3) = b.project

Answer 2

PLEASE VOID USING RESERVED KEYWORDS LIKE DESC

SQL Fiddle

MS SQL Server 2017 Schema Setup :

CREATE TABLE Table1 ([DESC] varchar(255))
CREATE TABLE Table2 (Project varchar(255))
INSERT INTO Table1([DESC])values('2AB F YY')
INSERT INTO Table2(Project)values('2AB')

Query 1 :

select SUBSTRING(a.[DESC],1,3)
from Table1 a
join Table2 b
on SUBSTRING(a.[DESC],1,3) = b.project

Results :

|     |
|-----|
| 2AB |