## All we need is an easy explanation of the problem, so here it is.

I am trying to get the distinguish column depending on another column’s value.

I was trying to approach with CASE function but could not get exactly what I wanted.

Condition

- if ColB has only 1 then online
- if ColB has only 2 then offline
- if ColB has both 1 and 2 then both
- if ColB does not have 1 or 2 then none

ColA | ColB |
---|---|

A | 1 |

A | 2 |

A | 1 |

B | 1 |

B | 1 |

C | 3 |

D | 2 |

D | 2 |

The result should be like this

ColA | distinguish |
---|---|

A | both |

B | online |

C | none |

D | offline |

Thanks!

## How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

### Method 1

Looks like you just need conditional `COUNT`

```
SELECT
t.ColA,
CASE WHEN COUNT(CASE WHEN t.ColB = '1' THEN 1 END) > 0 THEN
CASE WHEN COUNT(CASE WHEN t.ColB = '2' THEN 1 END) > 0 THEN
'both'
ELSE
'online'
END
ELSE
CASE WHEN COUNT(CASE WHEN t.ColB = '2' THEN 1 END) > 0 THEN
'offline'
ELSE
'none'
END
END
FROM YourTable t
GROUP BY
t.ColA;
```

### Method 2

This is just another way to skin the same cat, using a conditional `COUNT(DISTINCT)`

and a conditional `MAX()`

:

```
SELECT
ColA
, distinguish =
CASE COUNT(DISTINCT CASE WHEN ColB IN ('1', '2') THEN ColB END)
WHEN 0 THEN 'none'
WHEN 2 THEN 'both'
ELSE
CASE MAX(CASE WHEN ColB IN ('1', '2') THEN ColB END)
WHEN '1' THEN 'online'
ELSE 'offline'
END
END
FROM
dbo.YourTable
GROUP BY
ColA
;
```

**Note: Use and implement method 1 because this method fully tested our system.Thank you 🙂**

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0