How Do Wildcards Differ in Microsoft Jet's LIKE Operator Based on Query Mode?

Microsoft Jet's LIKE Operator: Wildcard Behavior Based on Query Mode

The Microsoft Jet database engine's LIKE operator uses different multi-character wildcards depending on the active ANSI query mode.

ANSI-89 Query Mode (Legacy Mode)

In ANSI-89 (legacy) mode, the asterisk (*) acts as the multi-character wildcard. This mode is generally associated with the DAO (Data Access Objects) interface.

ANSI-92 Query Mode (SQL Server Compatibility Mode)

Conversely, ANSI-92 mode (often used with ADO – ActiveX Data Objects – and the MS Access UI since version 2003) employs the percentage sign (%) as the multi-character wildcard.

ODBC and Explicit Mode Selection

When interacting with Jet via ODBC (Open Database Connectivity), the ExtendedAnsiSQL flag provides explicit control over the query mode, allowing you to select either ANSI-89 or ANSI-92 behavior.

The ALIKE Keyword (Unofficial)

Microsoft Jet SQL includes the ALIKE keyword. While it allows the use of ANSI-92 wildcards (% and _) regardless of the chosen query mode, it's crucial to remember that this keyword lacks official support and may not fully adhere to SQL-92 standards. Use with caution.

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