> For the complete documentation index, see [llms.txt](https://support.powerio.com/hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.powerio.com/hub/codesys-hvac/mysql-library/beispiele/werte-und-sonderzeichen.md).

# Werte und Sonderzeichen

## Werte und Sonderzeichen

In CODESYS müssen Sonderzeichen in Strings mit `$` kodiert werden.

#### Wichtigste $ Codes

| Zeichen                 | Code  | Verwendung      | Beispiel               |
| ----------------------- | ----- | --------------- | ---------------------- |
| `'` (Apostroph)         | `$27` | Text in SQL     | `$27Max Mustermann$27` |
| `"` (Anführungszeichen) | `$22` | Selten benötigt | `$22Text$22`           |
| `$` (Dollar)            | `$$`  | Dollar-Zeichen  | `$$100`                |

### Praktische Beispiele

#### Text-Werte in SQL einfügen

```iecst
// Falsch - funktioniert nicht:
MySQL_Command[0] := 'INSERT INTO users (name) VALUES ('Max')';

// Richtig - mit $27:
MySQL_Command[0] := 'INSERT INTO users (name) VALUES ($27Max$27)';
```

#### Dynamische Text-Werte

```iecst
VAR
    sName : STRING := 'Max Mustermann';
    sCity : STRING := 'Berlin';
END_VAR

// Text mit $27 einschließen
MySQL_Command[0] := 'INSERT INTO users (name, city) VALUES ($27';
MySQL_Command[1] := CONCAT(sName, '$27, $27');
MySQL_Command[2] := CONCAT(sCity, '$27)');

// Ergebnis: INSERT INTO users (name, city) VALUES ('Max Mustermann', 'Berlin')
```

#### WHERE-Bedingung mit Text

```iecst
VAR
    sSearchName : STRING := 'Schmidt';
END_VAR

MySQL_Command[0] := 'SELECT * FROM users WHERE name = $27';
MySQL_Command[1] := CONCAT(sSearchName, '$27');

// Ergebnis: SELECT * FROM users WHERE name = 'Schmidt'
```

#### Datum und Zeit

```iecst
// Datum
MySQL_Command[0] := 'SELECT * FROM logs WHERE date = $272024-01-15$27';

// Datum und Zeit
MySQL_Command[0] := 'SELECT * FROM logs WHERE timestamp = $272024-01-15 10:30:00$27';
```

#### Zahlen brauchen kein $27

```iecst
// Richtig - Zahlen ohne $27:
MySQL_Command[0] := 'INSERT INTO data (value) VALUES (123)';

// Falsch - nicht bei Zahlen:
MySQL_Command[0] := 'INSERT INTO data (value) VALUES ($27123$27)';  // FALSCH!
```

#### NULL-Werte

```iecst
// Richtig - NULL ohne $27:
MySQL_Command[0] := 'INSERT INTO data (value) VALUES (NULL)';

// Falsch:
MySQL_Command[0] := 'INSERT INTO data (value) VALUES ($27NULL$27)';  // FALSCH!
```

### Referenz

#### Datentyp -> SQL Format

| CoDeSys Typ  | SQL Format                  | Beispiel Code               |
| ------------ | --------------------------- | --------------------------- |
| **STRING**   | `$27text$27`                | `$27Berlin$27`              |
| **INT**      | Direkt                      | `123`                       |
| **REAL**     | Direkt (mit Punkt)          | `23.5`                      |
| **BOOL**     | Als 0/1 oder Text           | `1` oder `$27TRUE$27`       |
| **DATE**     | `$27YYYY-MM-DD$27`          | `$272024-01-15$27`          |
| **TIME**     | `$27HH:MM:SS$27`            | `$2710:30:00$27`            |
| **DATETIME** | `$27YYYY-MM-DD HH:MM:SS$27` | `$272024-01-15 10:30:00$27` |

### Häufige Fehler vermeiden

#### Falsch

```iecst
MySQL_Command[0] := 'INSERT INTO users (name) VALUES ('Max')';  
// Syntaxfehler!
```

#### Richtig

```iecst
MySQL_Command[0] := 'INSERT INTO users (name) VALUES ($27Max$27)';
```

#### Falsch

```iecst
MySQL_Command[0] := 'INSERT INTO data (value) VALUES ($27100$27)';  
// Zahl als Text!
```

#### Richtig

```iecst
MySQL_Command[0] := 'INSERT INTO data (value) VALUES (100)';
```


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