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here are some of most widely used and very important sql commands:

Table Store_Information

We shall use this table as an example throughout the tutorial (this table will appear in all sections). To select all the stores in this table, we key in,

SELECT store_name FROM Store_Information

Result:

Multiple column names can be selected, as well as multiple table names.

The SELECT keyword allows us to grab all information from a column (or columns) on a table. This, of course, necessarily mean that there will be redundancies. What if we only want to select each DISTINCT element? This is easy to accomplish in SQL. All we need to do is to add DISTINCT after SELECT. The syntax is as follows:

SELECT DISTINCT "column_name"
FROM "table_name"

For example, to select all distinct stores in Table Store_Information,

Table Store_Information

we key in,

SELECT DISTINCT store_name FROM Store_Information

Result:

SQL WHERE :

Next, we might want to conditionally select the data from a table. For example, we may want to only retrieve stores with sales above $1,000. To do this, we use the WHERE keyword. The syntax is as follows:

SELECT "column_name"
FROM "table_name"
WHERE "condition"

For example, to select all stores with sales above $1,000 in Table Store_Information,

Table Store_Information

we key in,

SELECT store_name
FROM Store_Information
WHERE Sales > 1000

Result: