What does a BIND variable look like.

    select * from table where fld = ?1

What are BIND variables.

A bind variable is a placeholder within your SELECT statement that is replaced at run time with data you list in the gsSQL() function.
For any variable data used from the Google Sheet, it can be easily inserted into the SELECT statement.
You can use cell data directly within the SELECT string, but this data needs to be concatenated into the string properly - which takes extra work.
- This is especially true when trying to include DATE data in your select.
For any variable data needed more than once in the SELECT, it cuts down on duplication.

When used within an SQL server, it is used for
- SQL Injection attacks.
- Performance. The execution plan only needs to be created once.
gsSQL uses its own version of bind variables for
- Less coding
- Readability of SQL.

The basic syntax for using gsSQL is as follows:

gsSQL(statement, tableArr, columnTitle, …bindings)

statement - your SQL select string WITH bind data placeholders.
tableArr - the definition of all referenced table names, plus where it is located.
columnTitle - boolean indicating if column headers are included in return data.
…bindings - a list of all bind data needed in SELECT. There is no limit on the number of listed parameters here.

Here is the basic syntax for using:

=gsSQL("select * from table where fld = ?1", { {"table", "table", 0} }, true, "idData")

The ?1 will be substituted at run time. The actual select would be run like this:
```
select * from table where fld = 'idData'
```

The number after the question mark indicates which bind data item should be used based on its position in the list.

=gsSQL("select * from table where fld = ?1 and quantity < ?2 and price > ?3", { {"table", "table", 0} }, true, "idData", 10, 3.99)

This would be translated to

select * from table where fld = 'idData' and quantity < 10 and price > 3.99

The bind placeholders do not need to be used in the order they are listed and any variable can be reference more than once:

=gsSQL("select * from table where backOrder < ?2 and order > ?2 and fld = ?1", { {"table", "table", 0} }, true, "idData", 10)

In this example the startDate and endDate are named ranges that contain a date.

=gsSQL("select * from table where date >= ?1 and date <= ?2", { {"table", "table", 0} }, true, startDate, endDate)

You can also use A1 cell notation:

=gsSQL("select * from table where date >= ?1 and date <= ?2", { {"table", "table", 0} }, true, A1, A2)

You can use a TAB name as a table. It is not necessary to define the table portion of the gsSQL() statement. Just leave the table defintion as an empty parameter:
This example MUST have a TAB named booksales with a column title date and named ranges called startDate and endDate (which can be anywhere in your spreadsheet).

=gsSQL("select * from booksales where date >= ?1 and date <= ?2", , true, startDate, endDate)