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Codeblock styles and minor typos
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kaitlinnewson committed Aug 29, 2023
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2 changes: 1 addition & 1 deletion episodes/02-selecting-sorting-data.md
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Expand Up @@ -41,7 +41,7 @@ In the first query above, we have capitalized the words `SELECT` and `FROM` beca

Example:

```
```sql
SELECT Title, Authors, ISSNs, Year
FROM Articles;
```
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4 changes: 2 additions & 2 deletions episodes/04-ordering-commenting.md
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Expand Up @@ -72,9 +72,9 @@ their effects as we went along. For complex queries, this is a good strategy, t

When the queries become more complex, it can be useful to add comments to express to yourself, or to others, what you are doing with your query. Comments help explain the logic of a section and provide context for anyone reading the query. It's essentially a way of making notes within your SQL. In SQL, comments begin using <code class="language-plaintext highlighter-rouge">\--</code> and end at the end of the line. To mark a whole paragraph as a comment, you can enclose it with the characters /\* and \*/. For example, a commented version of the above query can be written as:

```
```sql
/*In this section, even though JOINS (see link below this code block) are not introduced until Episode 6, we want to give an example how to
join multiple tables becasue they represent a good example of using comments in SQL to explain more complex queries.*/
join multiple tables because they represent a good example of using comments in SQL to explain more complex queries.*/

-- First we mention all the fields we want to display
SELECT articles.Title, articles.First_Author, journals.Journal_Title, publishers.Publisher
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2 changes: 1 addition & 1 deletion episodes/06-joins-aliases.md
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Expand Up @@ -107,7 +107,7 @@ ON publishers.id = journals.PublisherId;

::::::::::::::::::::::::::::::::::::::: challenge

## Challenge:
## Challenge

Write a query that returns the `Journal_Title`, `Publisher` name, and number of
articles published, ordered by number of articles in descending order.
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2 changes: 1 addition & 1 deletion episodes/08-database-design.md
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Expand Up @@ -76,7 +76,7 @@ Conceptually, we know that a journal has only one publisher but a publisher can

## More Terminology

The degree of relationship between entities is known as their 'cardinality'. Using the journals-publishers example, the 'publisheres' tble contains a primary key (PK) called 'id'. When the PK is used to create a connection between the original table and a different table, it is called a foreign key (FK) in the other table. To follow the example, we see a field in the 'journal' table called PublisherID that contains the values from the 'id' field in the 'publisher' table, connected the two tables.
The degree of relationship between entities is known as their 'cardinality'. Using the journals-publishers example, the 'publishers' table contains a primary key (PK) called 'id'. When the PK is used to create a connection between the original table and a different table, it is called a foreign key (FK) in the other table. To follow the example, we see a field in the 'journal' table called PublisherID that contains the values from the 'id' field in the 'publisher' table, connecting the two tables.

There are 4 main types of relationships between tables:

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2 changes: 1 addition & 1 deletion episodes/09-create.md
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Expand Up @@ -175,7 +175,7 @@ stored in any particular order.)

::::::::::::::::::::::::::::::::::::::::::::::::::

Adaped from the Software Carpentry Course "Databases and SQL", Chapter 9. 'Creating and Modifying Data'.
Adapted from the Software Carpentry Course "Databases and SQL", Chapter 9. 'Creating and Modifying Data'.
<https://swcarpentry.github.io/sql-novice-survey/09-create>

:::::::::::::::::::::::::::::::::::::::: keypoints
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28 changes: 14 additions & 14 deletions learners/reference.md
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Expand Up @@ -8,28 +8,28 @@ title: 'SQL Cheat Sheet'

### Basic query

```
```sql
SELECT column_names
FROM table_name;
```

- selects only the specified columns from a table.

```
```sql
SELECT *
FROM table_name;
```

- select all of the columns in a table.

```
SELECT DINSTINCT column_name
```sql
SELECT DISTINCT column_name
FROM table_name;
```

- selects only the unique values from a table.

```
```sql
SELECT column_names
FROM table_name
WHERE column_name operator value;
Expand All @@ -39,15 +39,15 @@ WHERE column_name operator value;
- you can use operators `=`,`<`,`>`, etc
- you can also combine tests using `AND`, `OR` in the WHERE clause.

```
```sql
SELECT column_names
FROM table_name
WHERE column_name IN (value1, value2, value3);
```

- selects only the data where column\_name equals to `value1`, `value2`, and so on.

```
```sql
SELECT column_names
FROM table_name
ORDER BY column_name ASC;
Expand All @@ -59,7 +59,7 @@ ORDER BY column_name ASC;

### Aggregation

```
```sql
SELECT aggregate_function(column_name)
FROM table_name;
```
Expand All @@ -68,7 +68,7 @@ FROM table_name;
- E.g. `SELECT COUNT(*) FROM table_name` will display the total number of records.
- You can use aggregate functions `COUNT`, `SUM`, `MAX`, `MIN`, `AVG`.

```
```sql
SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
Expand All @@ -77,7 +77,7 @@ GROUP BY column_name;

- `GROUP BY` tells SQL what field or fields we want to use to aggregate the data. If we want to group by multiple fields, we give `GROUP BY` a comma separated list.

```
```sql
SELECT column_name, aggregate_function(column_name)
FROM table_name
GROUP BY column_name
Expand All @@ -90,7 +90,7 @@ HAVING aggregate_function(column_name) operator value;

### Joins and aliases

```
```sql
SELECT column_names
FROM table_name1
JOIN table_name2
Expand All @@ -100,7 +100,7 @@ ON table_name1.column_name = table_name2.column_name;
- Combine data from two tables where the values of column\_name in the two tables are the same.
- Instead of `ON`, you can use the `USING` keyword as a shorthand. E.g. `USING (coolumn_name)`.

```
```sql
SELECT alias1.column_name1, alias1.column_name2, alias2.column_name3
FROM table_name1 AS alias1
JOIN table_name2 AS alias2
Expand All @@ -114,7 +114,7 @@ ON alias1.column_name = alias2.column_name;

### Saving queries

```
```sql
CREATE VIEW viewname AS
SELECT column_names
FROM table_name;
Expand All @@ -126,7 +126,7 @@ FROM table_name;

### Commenting

```
```sql
-- Select all columns
SELECT *
-- From the table_name
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