SQL Reference Guide

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SQL Language Elements

This chapter describes language elements that are common to many c-treeACE SQL statements. Syntax diagrams in other chapters often refer to these language elements without detailed explanation. The major syntax elements described in the following sections are:

Identifiers - User-supplied names for elements such as tables, views, cursors, and columns. c-treeACE SQL statements use those names to refer to the elements.

Data types - Control how c-treeACE SQL stores column values.

Query expressions - Retrieve values from tables. Query expressions form the basis of other c-treeACE SQL statements and syntax elements.

Search conditions - Specify a condition that is true or false about a given row or group of rows. Query expressions and UPDATE statements specify search conditions to restrict the number of rows in the result table.

Expressions - A symbol or string of symbols used to represent or calculate a single value in a c-treeACE SQL statement. When c-treeACE SQL encounters an expression, it retrieves or calculates the value represented by the expression and uses that value when it executes the statement.

Literals - A type of c-treeACE SQL expression that specify a constant value. Some SQL constructs allow literals but prohibit other forms of expressions.

Date-time format strings - Control the output of date and time values. c-treeACE SQL interprets format strings and replaces them with formatted values.

Functions - A type of c-treeACE SQL expression that returns a value based on the argument supplied. Aggregate functions calculate a single value for a collection of rows in a result table. Scalar functions calculate a value based on another single value.

In This Chapter

c-treeACE SQL Identifiers

Data Types

Search Conditions



Query Expressions

Inner Joins

Outer Joins

Date-Time Format Strings