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INSERT, UPDATE and DELETE

How to put records into a table, change them and how to take them out again.

• INSERT is used to add records.
• UPDATE can change an existing record.
• DELETE removes records.
• 'INSERT..SELECT' copies data from a SELECT into a table.
• INSERT: Not all fields need be specified. Default values may be specified in the CREATE TABLE clause - otherwise NULL is used.
• Insert a date.
• Explicitly enter a NULL.
• Can't INSERT because of reference.
• Cannot DELETE because of reference.
• Can't insert data because of incompatable formats.
• String contains a quote '
• to select the data from 20 different columns into one changing the values according to one other column consisting the positions of the 20 columns