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SET ENGINEBEHAVIOR Command

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Enables SQL data engine compatibility with Visual FoxPro 7.0 or Visual FoxPro 8.0.

SET ENGINEBEHAVIOR 70 | 80

Parameters

  • 70
    Specifies that Visual FoxPro treats SQL SELECT commands as it did in versions prior to Visual FoxPro 8.0
  • 80
    Specifies that Visual FoxPro treats SQL SELECT commands as follows. (Default)
    SQL SELECT clause Behavior
    DISTINCT You cannot use the DISTINCT clause with Memo or General fields. Instead, wrap a Memo field inside a function such as PADR( ) or ALLTRIM( ).

    For more information, see PADL( ) | PADR( ) | PADC( ) Functions and ALLTRIM( ) Function.
    UNION The UNION clause does not support Memo fields unless the ALL clause is included in the SQL SELECT statement.
    GROUP BY The GROUP BY clause does not support Memo or General fields.

    The GROUP BY clause must list every field in the SELECT list except for fields contained in an aggregate function, such as the COUNT( ) function. In addition, the GROUP BY clause must also list every field in a HAVING clause except for fields contained in an aggregate function.

    For example, the following code raises an error because the field company is not listed in the GROUP BY clause.

    SELECT company, country FROM Customer GROUP BY country

    You can include an aggregate function in the SELECT list without having it in the GROUP BY clause.

    For example, the following code uses the COUNT( ) function on the field company without having the field company in the GROUP BY clause.

    SELECT COUNT(company), country FROM Customer GROUP BY country
    HAVING A SQL SELECT statement can contain the HAVING clause without the GROUP BY clause as long as the SQL SELECT statement does not contain any aggregate functions.

    For example, the following code filters query results by specifying the country field must equal "Sweden".

    SELECT customerid FROM customers HAVING country="Sweden"
    LIKE SQL SELECT statements do not automatically remove trailing spaces from values compared with the LIKE operation. In versions prior to Visual FoxPro 8.0, both values in the LIKE operation were trimmed from the right prior to evaluation.

    For example, the following code assumes that you have a table named table1, and the table has three rows that contain values of "1 ", "12 ", and "123", respectively.

    SELECT * FROM table1 WHERE column1 LIKE "1__"

    Visual FoxPro version 7.0 and earlier returns one row with the value of "123". Visual FoxPro 8.0 returns three rows with the values, "1 ", "12 ", and "123".

    If the beginning of the filter condition matches the pattern of the expression in the LIKE operation, and the rest of the filter condition contains trailing spaces, the LIKE operation ignores the trailing spaces and returns True (.T.). Trailing spaces in the pattern are not ignored.

Remarks

Using SET ENGINEBEHAVIOR set to 70 might lead to ambiguous results from SQL SELECT commands when the DISTINCT and UNION clauses are used with memos and the GROUP BY clause, the HAVING clause without a GROUP BY clause, and when using the LIKE clause.

The scope of SET ENGINEBEHAVIOR is global.

See Also

SET Command Overview | SELECT - SQL Command | Special Terms for Configuration Files | SYS(3099) - SQL Data Engine Compatibility Mode