// The return type of a CASE expression is the compatible aggregated type of all return values,
// but also depends on the context in which it is used.
// If used in a string context, the result is returned as a string.
// If used in a numeric context, the result is returned as a decimal, real, or integer value.
func (v *typeInferrer) handleCaseExpr(x *ast.CaseExpr) {
var currType *types.FieldType
for _, w := range x.WhenClauses {
t := w.Result.GetType()
if currType == nil {
currType = t
continue
}
mtp := types.MergeFieldType(currType.Tp, t.Tp)
if mtp == t.Tp && mtp != currType.Tp {
currType.Charset = t.Charset
currType.Collate = t.Collate
}
currType.Tp = mtp
}
if x.ElseClause != nil {
t := x.ElseClause.GetType()
if currType == nil {
currType = t
} else {
mtp := types.MergeFieldType(currType.Tp, t.Tp)
if mtp == t.Tp && mtp != currType.Tp {
currType.Charset = t.Charset
currType.Collate = t.Collate
}
currType.Tp = mtp
}
}
x.SetType(currType)
// TODO: We need a better way to set charset/collation
x.Type.Charset, x.Type.Collate = types.DefaultCharsetForType(x.Type.Tp)
}
func (v *typeInferrer) handleFuncCallExpr(x *ast.FuncCallExpr) {
var (
tp *types.FieldType
chs = charset.CharsetBin
)
switch x.FnName.L {
case "abs", "ifnull", "nullif":
tp = x.Args[0].GetType()
case "pow", "power", "rand":
tp = types.NewFieldType(mysql.TypeDouble)
case "curdate", "current_date", "date":
tp = types.NewFieldType(mysql.TypeDate)
case "curtime", "current_time":
tp = types.NewFieldType(mysql.TypeDuration)
tp.Decimal = v.getFsp(x)
case "current_timestamp":
tp = types.NewFieldType(mysql.TypeDatetime)
case "microsecond", "second", "minute", "hour", "day", "week", "month", "year",
"dayofweek", "dayofmonth", "dayofyear", "weekday", "weekofyear", "yearweek",
"found_rows", "length":
tp = types.NewFieldType(mysql.TypeLonglong)
case "now", "sysdate":
tp = types.NewFieldType(mysql.TypeDatetime)
tp.Decimal = v.getFsp(x)
case "dayname", "version", "database", "user", "current_user",
"concat", "concat_ws", "left", "lower", "repeat", "replace", "upper":
tp = types.NewFieldType(mysql.TypeVarString)
chs = v.defaultCharset
case "connection_id":
tp = types.NewFieldType(mysql.TypeLonglong)
tp.Flag |= mysql.UnsignedFlag
case "if":
// TODO: fix this
// See: https://dev.mysql.com/doc/refman/5.5/en/control-flow-functions.html#function_if
// The default return type of IF() (which may matter when it is stored into a temporary table) is calculated as follows.
// Expression Return Value
// expr2 or expr3 returns a string string
// expr2 or expr3 returns a floating-point value floating-point
// expr2 or expr3 returns an integer integer
tp = x.Args[1].GetType()
default:
tp = types.NewFieldType(mysql.TypeUnspecified)
}
// If charset is unspecified.
if len(tp.Charset) == 0 {
tp.Charset = chs
cln := charset.CollationBin
if chs != charset.CharsetBin {
var err error
cln, err = charset.GetDefaultCollation(chs)
if err != nil {
v.err = err
}
}
tp.Collate = cln
}
x.SetType(tp)
}
func (v *typeInferrer) handleFuncCallExpr(x *ast.FuncCallExpr) {
var (
tp *types.FieldType
chs = charset.CharsetBin
)
switch x.FnName.L {
case "abs", "ifnull", "nullif":
tp = x.Args[0].GetType()
case "pow", "power", "rand":
tp = types.NewFieldType(mysql.TypeDouble)
case "curdate", "current_date", "date":
tp = types.NewFieldType(mysql.TypeDate)
case "curtime", "current_time":
tp = types.NewFieldType(mysql.TypeDuration)
tp.Decimal = v.getFsp(x)
case "current_timestamp":
tp = types.NewFieldType(mysql.TypeDatetime)
case "microsecond", "second", "minute", "hour", "day", "week", "month", "year",
"dayofweek", "dayofmonth", "dayofyear", "weekday", "weekofyear", "yearweek",
"found_rows", "length":
tp = types.NewFieldType(mysql.TypeLonglong)
case "now", "sysdate":
tp = types.NewFieldType(mysql.TypeDatetime)
tp.Decimal = v.getFsp(x)
case "dayname", "version", "database", "user", "current_user",
"concat", "concat_ws", "left", "lower", "repeat", "replace", "upper":
tp = types.NewFieldType(mysql.TypeVarString)
chs = v.defaultCharset
case "connection_id":
tp = types.NewFieldType(mysql.TypeLonglong)
tp.Flag |= mysql.UnsignedFlag
case "if":
tp = x.Args[1].GetType()
default:
tp = types.NewFieldType(mysql.TypeUnspecified)
}
// If charset is unspecified.
if len(tp.Charset) == 0 {
tp.Charset = chs
cln := charset.CollationBin
if chs != charset.CharsetBin {
var err error
cln, err = charset.GetDefaultCollation(chs)
if err != nil {
v.err = err
}
}
tp.Collate = cln
}
x.SetType(tp)
}
func (d *ddl) setCharsetCollationFlenDecimal(tp *types.FieldType) {
if len(tp.Charset) == 0 {
switch tp.Tp {
case mysql.TypeString, mysql.TypeVarchar, mysql.TypeVarString, mysql.TypeBlob, mysql.TypeTinyBlob, mysql.TypeMediumBlob, mysql.TypeLongBlob:
tp.Charset, tp.Collate = getDefaultCharsetAndCollate()
default:
tp.Charset = charset.CharsetBin
tp.Collate = charset.CharsetBin
}
}
// If flen is not assigned, assigned it by type.
if tp.Flen == types.UnspecifiedLength {
tp.Flen = mysql.GetDefaultFieldLength(tp.Tp)
}
if tp.Decimal == types.UnspecifiedLength {
tp.Decimal = mysql.GetDefaultDecimal(tp.Tp)
}
}
func (v *typeInferrer) handleFuncCallExpr(x *ast.FuncCallExpr) {
var (
tp *types.FieldType
chs = charset.CharsetBin
)
switch x.FnName.L {
case "abs", "ifnull", "nullif":
tp = x.Args[0].GetType()
// TODO: We should cover all types.
if x.FnName.L == "abs" && tp.Tp == mysql.TypeDatetime {
tp = types.NewFieldType(mysql.TypeDouble)
}
case "greatest":
for _, arg := range x.Args {
InferType(v.sc, arg)
}
if len(x.Args) > 0 {
tp = x.Args[0].GetType()
for i := 1; i < len(x.Args); i++ {
mergeArithType(tp.Tp, x.Args[i].GetType().Tp)
}
}
case "ceil", "ceiling":
t := x.Args[0].GetType().Tp
if t == mysql.TypeNull || t == mysql.TypeFloat || t == mysql.TypeDouble || t == mysql.TypeVarchar ||
t == mysql.TypeTinyBlob || t == mysql.TypeMediumBlob || t == mysql.TypeLongBlob ||
t == mysql.TypeBlob || t == mysql.TypeVarString || t == mysql.TypeString {
tp = types.NewFieldType(mysql.TypeDouble)
} else {
tp = types.NewFieldType(mysql.TypeLonglong)
}
case "ln", "log", "log2", "log10":
tp = types.NewFieldType(mysql.TypeDouble)
case "pow", "power", "rand":
tp = types.NewFieldType(mysql.TypeDouble)
case "curdate", "current_date", "date":
tp = types.NewFieldType(mysql.TypeDate)
case "curtime", "current_time", "timediff":
tp = types.NewFieldType(mysql.TypeDuration)
tp.Decimal = v.getFsp(x)
case "current_timestamp", "date_arith":
tp = types.NewFieldType(mysql.TypeDatetime)
case "microsecond", "second", "minute", "hour", "day", "week", "month", "year",
"dayofweek", "dayofmonth", "dayofyear", "weekday", "weekofyear", "yearweek",
"found_rows", "length", "extract", "locate":
tp = types.NewFieldType(mysql.TypeLonglong)
case "now", "sysdate":
tp = types.NewFieldType(mysql.TypeDatetime)
tp.Decimal = v.getFsp(x)
case "from_unixtime":
if len(x.Args) == 1 {
tp = types.NewFieldType(mysql.TypeDatetime)
} else {
tp = types.NewFieldType(mysql.TypeVarString)
chs = v.defaultCharset
}
case "str_to_date":
tp = types.NewFieldType(mysql.TypeDatetime)
case "dayname", "version", "database", "user", "current_user", "schema",
"concat", "concat_ws", "left", "lcase", "lower", "repeat",
"replace", "ucase", "upper", "convert", "substring",
"substring_index", "trim", "ltrim", "rtrim", "reverse", "hex", "unhex", "date_format":
tp = types.NewFieldType(mysql.TypeVarString)
chs = v.defaultCharset
case "strcmp", "isnull":
tp = types.NewFieldType(mysql.TypeLonglong)
case "connection_id":
tp = types.NewFieldType(mysql.TypeLonglong)
tp.Flag |= mysql.UnsignedFlag
case "if":
// TODO: fix this
// See https://dev.mysql.com/doc/refman/5.5/en/control-flow-functions.html#function_if
// The default return type of IF() (which may matter when it is stored into a temporary table) is calculated as follows.
// Expression Return Value
// expr2 or expr3 returns a string string
// expr2 or expr3 returns a floating-point value floating-point
// expr2 or expr3 returns an integer integer
tp = x.Args[1].GetType()
case "get_lock", "release_lock":
tp = types.NewFieldType(mysql.TypeLonglong)
default:
tp = types.NewFieldType(mysql.TypeUnspecified)
}
// If charset is unspecified.
if len(tp.Charset) == 0 {
tp.Charset = chs
cln := charset.CollationBin
if chs != charset.CharsetBin {
var err error
cln, err = charset.GetDefaultCollation(chs)
if err != nil {
v.err = err
}
}
tp.Collate = cln
}
x.SetType(tp)
}
