SQL 101

What is SQL?

SQL is the abbreviation for Structured Query Language pronounced one of two ways; SEQUEL or ESS-Q-L

Talking to SQL

Firstly a connection to a SQL database must be made. With SQL tools, you can use Enterprise Manager or in Visual FoxPro create a data source connection and then use the SQLCONNECT(datasource, username, password)

Once you have a File Handle, you can then use SQLEXEC(FH, [SQL Command], [cCursor])

Show me the Data

To get the data

SELECT [ALL | DISTINCT] [column1, column2, ]
FROM [table1, table2]
WHERE conditions
GROUP BY [column-list]
HAVING "conditions "
ORDER BY "column-list" ASC | DESC

Delete Data

Tip: You cannot get back deleted data without a backup
Tip 2: Before doing a delete, I always use a select first, verify that the result set is what I want to delete and then change the SELECT to a DELETE

DELETE FROM <table> WHERE condition

Updating Data

UPDATE <table> SET FIELD Field1 = SomeValue WHERE condition