The Expression Editor helps you create search conditions, computed columns, and subqueries. To edit existing expressions, highlight the expression before you open the Expression Editor. Otherwise, what you create in the Expression Editor is appended to previously existing expressions when you click OK.
Expression This is where you build your expression.
Columns This box lists the columns that are in your query. To insert a column into your expression, double-click it here, or type it directly into the Expression box.
Functions Functions are predefined expressions used to return information about the database. To insert a function into your expression, choose it from the dropdown list.
See SQL Functions.
Stored Procedures This box lists the stored procedures that you can use.
Numeric keypad The numeric keypad is located in the bottom left section of the dialog. Click a number to insert it into the expression. You can also type numbers from your keyboard.
Comparison operators These arithmetic symbols, such as =, appear in the middle of the bottom section of the dialog. Click a symbol to insert it into the expression. Only a subset of common operators are included here, but you can type others from your keyboard.
See Comparison operators.
Logical operators Logical operators, such as AND, appear in the right bottom section of the dialog. Click an operator to insert it into the expression. This group is a subset of commonly used logical operators. You can use any logical operator by typing it from your keyboard.
See Logical operators.
Create a subquery button The subquery button is located with the logical operators. Click it to access a dialog that guides you in creating subqueries.
To create a subquery, open the Expression Editor and click the Subquery button (located next to the NOT button). This opens the Subquery dialog, which looks identical to the main Query Editor except that the word Subquery is in the title bar. You create a subquery just as you create a main query.
To edit a subquery in the Query Editor, highlight the subquery in the Criteria box, and click the Expression Editor button. Highlight the code in the Expression Editor, and click the Subquery button.