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Select data

  • Стаття

The select statement fetches or manipulates data from the database.

  • All select statements use a table variable to fetch records. This variable must be declared before a select statement can be run.

  • The select statement fetches only one record, or field. To fetch or traverse multiple records, you can use the next statement or the while select statement.

    • The next statement fetches the next record in the table. If no select statement precedes the next statement, an error occurs. If you use a next statement, don't use the firstOnly find option.
    • It's more appropriate to use a while select statement to traverse multiple records.

  • The results of a select statement are returned in a table buffer variable.

  • If you use a field list in the select statement, only those fields are available in the table variable.

The following example fetches all the columns in the first row of the CustTable table and prints the value in the AccountNum column of that row.

CustTable custTable;
select firstonly custTable; //this is a short notation for 'select firstonly * from custTable;'  
info("AccountNum: " + custTable.AccountNum);

The following example prints the value in the AccountNum column of each row in the CustTable table.

CustTable custTable;
while select custTable
{
    info("AccountNum: " + custTable.AccountNum);
}

The following example prints the value in the AccountNum column of the first two rows that are returned by the select statement.

CustTable custTable;
select custTable;
info("AccountNum: " + custTable.AccountNum);

next custTable;
info("AccountNum: " + custTable.AccountNum);

For more examples, see Select statement.