[英]How to [MySQL] select users with records
I have these tables: 我有这些表:
users : 用户 :
|user_id|user_name|
|-------|---------|
| 1 | John |
|-------|---------|
| 2 | Mark |
|-------|---------|
| 3 | Paul |
|-------|---------|
records : 记录 :
| record_id | user_id | records |
|-----------|---------|--------------|
| 1 | 3 | lorem ipsum |
|-----------|---------|--------------|
| 2 | 3 | dolor sit |
|-----------|---------|--------------|
| 3 | 3 | consectetur |
|-----------|---------|--------------|
| 4 | 1 | adipisicing |
|-----------|---------|--------------|
| 5 | 3 | eiusmod |
|-----------|---------|--------------|
| 6 | 1 | consectetur |
|-----------|---------|--------------|
What I want is to select users who have records. 我想要的是选择具有记录的用户。 In this case, only John and Paul should return.
在这种情况下,只有约翰和保罗应该回来。
Using a subquery: 使用子查询:
SELECT user_name FROM users WHERE user_id IN (SELECT DISTINCT user_id FROM records)
Or using an INNER JOIN: 或使用内部联接:
SELECT u.user_name FROM users u
INNER JOIN records r ON u.user_id=r.user_id
GROUP BY u.user_name
SELECT u.user_name, r.records FROM users as u, records as r where u.user_id = r.user_id
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