using System.Data.SqlTypes; namespace SqlNullsCS { class Program { static void Main() { CompareNulls(); Console.ReadLine(); } private static void CompareNulls() { // Create two new null strings. SqlString a = new SqlString(); SqlString b = new SqlString(); // Compare nulls using ...
Initializes a new instance of theSqlParameterclass that uses the parameter name, the type of the parameter, the length of the parameter the direction, the precision, the scale, the name of the source column, one of theDataRowVersionvalues, a Boolean for source column mapping, the value of ...
Nullable<int> i =null; Nullable<int> j =null;if(i == j) {// This branch is executed.} SQL -- Assume col1 and col2 are integer columns with null values.-- Assume that ANSI null behavior has not been explicitly-- turned off.Select…From…Wherecol1 = col2-- Evaluates to null, ...
[Serializable] [Microsoft.SqlServer.Server.SqlUserDefinedType(Format.Native, IsByteOrdered=true)]publicstructPoint : INullable { ... } 实现可为 null 性 除了为您的程序集正确指定属性外,UDT 还必须支持为 Null 性。 加载到 SQL Server 中的 UDT 具有 null 感知性,但为了使 UDT 能够识别 null 值,UDT...
If all arguments areNULL,COALESCEreturnsNULL. At least one of the null values must be a typedNULL. Compare COALESCE and CASE TheCOALESCEexpression is a syntactic shortcut for theCASEexpression. That is, the codeCOALESCE(<expression1>, ...n)is rewritten by the query optimizer as the following...
For example, after reselecting a row using rowid, the application can compare the previous values in the SQL_ROWVER columns to the ones just fetched. If the value in a SQL_ROWVER column differs from the previous value, the application can alert the user that data on the display has ...
stringValue.CompareTo(strB)案例當時 @stringValue = @strB 為 0 ...結束 stringValue.Contains(value)@stringValue LIKE N'%' + @value + N'%' stringValue.EndsWith(value)@stringValue LIKE N'%' + @value stringValue.FirstOrDefault()SUBSTRING(@stringValue, 1, 1) ...
The equal (=) operator is used to compare two expressions values and if the compared values are equal the comparison result will be true. On the other hand, when we try to use an equal operator to find the rows that contain the null values, the result set will return nothing. For exam...
Gets or sets the CompareInfo object that defines how string comparisons should be performed for this parameter. DbType Gets or sets the SqlDbType of the parameter. Direction Gets or sets a value that indicates whether the parameter is input-only, output-only, bidirectional, or a stored proce...
insert into test:test_sql (row_key, f1:id , f1:name , f1:age ) values ('r1', 'id1_v1' , 'leo1_v1' , 11 ) 插入多条数据 insert into test:test_sql (row_key, f1:id , f1:name , f1:age ) values ('r1', 'id1_v1' , 'leo1_v1' , 11 ), ('r2', 'id2_v1' ...