本文整理汇总了Golang中github.com/pingcap/tidb/util/types.Datum.SetNull方法的典型用法代码示例。如果您正苦于以下问题：Golang Datum.SetNull方法的具体用法？Golang Datum.SetNull怎么用？Golang Datum.SetNull使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类github.com/pingcap/tidb/util/types.Datum的用法示例。
在下文中一共展示了Datum.SetNull方法的5个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Golang代码示例。
示例1: TestEvalCoalesce
func (s *testEvalSuite) TestEvalCoalesce(c *C) {
colID := int64(1)
row := make(map[int64]types.Datum)
row[colID] = types.NewIntDatum(100)
xevaluator := &Evaluator{Row: row}
nullDatum := types.Datum{}
nullDatum.SetNull()
notNullDatum := types.NewStringDatum("not-null")
cases := []struct {
expr *tipb.Expr
result types.Datum
}{
{
expr: buildExpr(tipb.ExprType_Coalesce, nullDatum, nullDatum, nullDatum),
result: nullDatum,
},
{
expr: buildExpr(tipb.ExprType_Coalesce, nullDatum, notNullDatum, nullDatum),
result: notNullDatum,
},
{
expr: buildExpr(tipb.ExprType_Coalesce, nullDatum, notNullDatum, types.NewStringDatum("not-null-2"), nullDatum),
result: notNullDatum,
},
}
for _, ca := range cases {
result, err := xevaluator.Eval(ca.expr)
c.Assert(err, IsNil)
c.Assert(result.Kind(), Equals, ca.result.Kind())
cmp, err := result.CompareDatum(xevaluator.sc, ca.result)
c.Assert(err, IsNil)
c.Assert(cmp, Equals, 0)
}
}示例2: evalXor
// evalXor computes result of (X XOR Y).
func (e *Evaluator) evalXor(leftBool, rightBool int64) (types.Datum, error) {
var d types.Datum
if leftBool == compareResultNull || rightBool == compareResultNull {
d.SetNull()
return d, nil
}
if leftBool == rightBool {
d.SetInt64(0)
return d, nil
}
d.SetInt64(1)
return d, nil
}示例3: evalOr
func (e *Evaluator) evalOr(expr *tipb.Expr) (types.Datum, error) {
leftBool, rightBool, err := e.evalTwoBoolChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
var d types.Datum
if leftBool == 1 || rightBool == 1 {
d.SetInt64(1)
return d, nil
}
if leftBool == compareResultNull || rightBool == compareResultNull {
d.SetNull()
return d, nil
}
d.SetInt64(0)
return d, nil
}示例4: builtinStrToDate
// See https://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_str-to-date
func builtinStrToDate(args []types.Datum, _ context.Context) (types.Datum, error) {
date := args[0].GetString()
format := args[1].GetString()
var (
d types.Datum
t types.Time
)
succ := t.StrToDate(date, format)
if !succ {
d.SetNull()
return d, nil
}
d.SetMysqlTime(t)
return d, nil
}示例5: TestEvalCaseWhen
func (s *testEvalSuite) TestEvalCaseWhen(c *C) {
colID := int64(1)
xevaluator := NewEvaluator(new(variable.StatementContext))
xevaluator.Row[colID] = types.NewIntDatum(100)
trueCond := types.NewIntDatum(1)
falseCond := types.NewIntDatum(0)
nullCond := types.Datum{}
nullCond.SetNull()
cases := []struct {
expr *tipb.Expr
result types.Datum
}{
{
expr: buildExpr(tipb.ExprType_Case,
falseCond, types.NewStringDatum("case1"),
trueCond, types.NewStringDatum("case2"),
trueCond, types.NewStringDatum("case3")),
result: types.NewStringDatum("case2"),
},
{
expr: buildExpr(tipb.ExprType_Case,
falseCond, types.NewStringDatum("case1"),
falseCond, types.NewStringDatum("case2"),
falseCond, types.NewStringDatum("case3"),
types.NewStringDatum("Else")),
result: types.NewStringDatum("Else"),
},
{
expr: buildExpr(tipb.ExprType_Case,
falseCond, types.NewStringDatum("case1"),
falseCond, types.NewStringDatum("case2"),
falseCond, types.NewStringDatum("case3")),
result: types.Datum{},
},
{
expr: buildExpr(tipb.ExprType_Case,
buildExpr(tipb.ExprType_Case,
falseCond, types.NewIntDatum(0),
trueCond, types.NewIntDatum(1),
), types.NewStringDatum("nested case when"),
falseCond, types.NewStringDatum("case1"),
trueCond, types.NewStringDatum("case2"),
trueCond, types.NewStringDatum("case3")),
result: types.NewStringDatum("nested case when"),
},
{
expr: buildExpr(tipb.ExprType_Case,
nullCond, types.NewStringDatum("case1"),
falseCond, types.NewStringDatum("case2"),
trueCond, types.NewStringDatum("case3")),
result: types.NewStringDatum("case3"),
},
}
for _, ca := range cases {
result, err := xevaluator.Eval(ca.expr)
c.Assert(err, IsNil)
c.Assert(result.Kind(), Equals, ca.result.Kind())
cmp, err := result.CompareDatum(xevaluator.sc, ca.result)
c.Assert(err, IsNil)
c.Assert(cmp, Equals, 0)
}
}