Use database name
go to
Select a different user
From cats
Where time ='' or time >'' or time <''
Sort by time
DESC
go to
If you want to convert the data of a column or a field from garbled to uppercase, use this function upper.
Upper Usage Limit (field)
The detailed explanation of sql function is as follows:
SQL function, described in detail as follows: Avg function Avg function, which calculates the arithmetic average of data in specific fields in the query. The syntax is Avg (expression). Expression, which can be a field name, an expression or a function. This function can be internal or user-defined, but it cannot be any other SQL function. When calculating, the Avg function does not contain any data with null value. Count function Count function calculates the number of records that meet the query conditions. The syntax is Count (expression). Expression, which can be field name *, multiple field names, expressions or functions. This function can be internal or user-defined, but it cannot be any other SQL function. When calculating the Count function, it does not contain any data with null values. However, Count(*) counts all records that meet the query criteria, including those empty data. If the field name of Count is called multiple fields, use&; Separate. The Count function will be counted as a record only when the value of at least one of the multiple fields is not empty. If multiple fields are empty, it is not a record. For example, select count (price &; Code) From product First/Last function The First function and the Last function return the data of the first and last records that meet the query conditions in the specified field. Grammar is First (expression) and Last (expression). Expression, which can be a field name, an expression or a function. This function can be internal or user-defined, but it cannot be any other SQL function. Minimum/Maximum Function The minimum and maximum functions return the minimum and maximum values that meet the query conditions in the specified field. The syntax is Min (expression) and Max (expression). Expression, which can be a field name, an expression or a function. This function can be internal or user-defined, but it cannot be any other SQL function. StDev function StDev function, calculate the standard deviation of the specified field that meets the query conditions. The syntax is StDev (expression). Expression, which can be a field name, an expression or a function. This function can be internal or user-defined, but it cannot be any other SQL function. If there are less than two records that meet the query criteria, the StDev function will return a null value, which means that the standard deviation cannot be calculated. Sum function Sum function, which calculates the sum of the data that meet the query conditions in the specified field. The syntax is Sum (expression). Expression, which can be a field name, an expression or a function. This function can be internal or user-defined, but it cannot be any other SQL function. The Sum function can use two kinds of field data expressions, such as calculating the sum of the unit price and quantity fields of the product: select sum (unit price * quantity) from the Var function of the product and calculate the estimated variance in the specified field that meets the query conditions. The syntax is Var (expression). Expression, which can be a field name, an expression or a function. This function can be internal or user-defined, but it cannot be any other SQL function. If there are less than two records that meet the query criteria, the Var function will return a null value, which means that variance cannot be calculated.